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COOLING SYSTEM

1. WARNING USE EXTREME CAUTION WHEN THE ENGINE IS OPERATING DO NOT STAND IN A DIRECT LINE WITH THE FAN DO NOT PUT YOUR HANDS NEAR THE PULLEYS BELTS OR FAN DO NOT WEAR LOOSE CLOTHING 6 Start the engine and operate at 2400 rpm Within ten minutes the air temperature indicated on the dial thermometer should be up to 88 C 190 F Fan drive engagement should have started to occur at between 74 to 82 C 165 to 180 F Engage ment is distinguishable by a definite increase in fan flow noise roaring The timing light also will indi cate an increase in the speed of the fan 7 When the air temperature reaches 88 C 190 F remove the plastic sheet Fan drive disengage ment should have started to occur at between 57 to 79 C 135 to 175 F A definite decrease of fan flow noise roaring should be noticed If not replace the defective viscous fan drive unit DN COOLING SYSTEM 7 19 DIAGNOSIS AND TESTING Continued ACCESSORY DRIVE BELT DIAGNOSIS VISUAL DIAGNOSIS When diagnosing serpentine accessory drive belts small cracks that run across the ribbed surface of the belt from rib to rib Fig 23 are considered normal These are not a reason to replace the belt However cracks running along a rib not across are not nor mal Any belt with cracks running along a rib must be replaced Fig 23 Also replace the belt if it has excessive wear frayed cords or severe glazing Refer to the Accessory Drive Belt D
2. DTC been set indicating a stuck open thermostat 2 Is the temperature sending unit connected 3 Is the temperature gauge operating OK 4 Coolant level low in cold ambient temperatures accompanied with poor heater performance 5 Improper operation of internal heater doors or heater controls 1 Refer to Group 25 Emission Systems for On Board Diagnostics and DTC information Replace thermostat if necessary 2 Check the temperature sensor connector Refer to Group 8E Repair connector if necessary 3 Check gauge operation Refer to Group 8E Repair as necessary 4 Check coolant level in the coolant reserve overflow tank and the radiator Inspect system for leaks Repair leaks as necessary Refer to the Coolant section of the manual text for WARNINGS and CAUTIONS associated with removing the radiator cap 5 Inspect heater and repair as necessary Refer to Group 24 Heating and Air Conditioning for procedures TEMPERATURE GAUGE READS HIGH OR THE COOLANT WARNING LAMP ILLUMINATES COOLANT MAY OR MAY NOT BE LOST OR LEAKING FROM THE COOLING SYSTEM 1 Trailer is being towed a steep hill is being climbed vehicle is operated in slow moving traffic or engine is being idled with very high ambient outside temperatures and the air conditioning is on Higher altitudes could aggravate these conditions 2 Is the temperature gauge reading correctly 3 Is the temperature warning illuminating unnecessar
3. Install thermostat spring side down into recessed machined groove on intake manifold Fig 46 3 Install gasket on intake manifold and over thermostat Fig 46 4 Position thermostat housing to intake manifold Note the word FRONT stamped on housing Fig 47 For adequate clearance this must be placed towards front of vehicle The housing is slightly angled for ward after installation to intake manifold 5 Install two housing to intake manifold bolts Tighten bolts to 23 N m 200 in Ibs torque 6 Install upper radiator hose to thermostat hous ing 7 Air Conditioned vehicles CAUTION When installing the serpentine acces sory drive belt the belt must be routed correctly If not engine may overheat due to water pump rotat ing in wrong direction Refer to Fig 48 for correct engine belt routing The correct belt with correct length must be used a Install generator Tighten bolts to 41 N m 30 ft Ibs 7 34 COOLING SYSTEM REMOVAL AND INSTALLATION Continued DN J9207 13 Fig 47 Thermostat Position 5 2L 5 9L Engines b Install support bracket generator mounting bracket to intake manifold Fig 44 Tighten bolts to 54 N m 40 ft Ibs torque c Position drive belt over all pulleys except idler pulley located between generator and A C compressor d Attach a socket wrench to pulley mounting bolt of automatic tensioner Fig 45 e Rotate socket wrench clockwise Place belt
4. cracked or separated from body of belt 1 Tension sheeting contacting stationary object 2 Excessive heat causing woven fabric to age 3 Tension sheeting splice has fractured 1 Correct rubbing condition 2 Replace belt 3 Replace belt CORD EDGE FAILURE Tensile member exposed at edges of belt or separated from belt body 1 Incorrect belt tension 2 Belt contacting stationary object 3 Pulley s out of tolerance 4 Insufficient adhesion between tensile member and rubber matrix 1 Inspect Replace tensioner if necessary 2 Replace belt 3 Replace pulley 4 Replace belt DN DIAGNOSIS AND TESTING Continued THERM OSTAT GAS ENGINES ON BOARD DIAGNOSTICS All gasoline powered models are equipped with On Board Diagnostics for certain cooling system com ponents Refer to On Board Diagnostics OBD in the Diagnosis section of this group for additional infor mation If the powertrain control module PCM detects low engine coolant temperature it will record a Diagnostic Trouble Code DTC in the PCM mem ory Do not change a thermostat for lack of heat as indicated by the instrument panel gauge or by poor heater performance unless a DTC is present Refer to the Diagnosis section of this group for other probable causes For other DTC numbers refer to On Board Diagnostics in the General Diagnosis section of Group 25 Emission Systems The DTC can also be accessed through the DRB scan tool Refer to
5. with 4WD unplug 4WD indicator lamp wiring har ness located near rear of generator f Remove generator Position generator to gain access for thermostat gasket removal hi TURN CLOCKWISE TO REMOVE BELT J9219 15 Fig 45 Automatic Belt Tensioner 5 2L 5 9L Engines 1 IDLER PULLEY 2 TENSIONER 3 FAN BLADE WARNING CONSTANT TENSION HOSE CLAMPS ARE USED ON MOST COOLING SYSTEM HOSES WHEN REMOVING OR INSTALLING USE ONLY TOOLS DESIGNED FOR SERVICING THIS TYPE OF CLAMP SUCH AS SPECIAL CLAMP TOOL NUMBER 6094 Fig 38 SNAP ON CLAMP TOOL NUMBER HPC 20 MAY BE USED FOR LARGER CLAMPS ALWAYS WEAR SAFETY GLASSES WHEN SERVIC ING CONSTANT TENSION CLAMPS CAUTION A number or letter is stamped into the tongue of constant tension clamps Fig 39 If replacement is necessary use only an original equipment clamp with matching number or letter 5 Remove upper radiator hose damp and upper radiator hose at thermostat housing 6 Position wiring harness behind thermostat housing to gain access to thermostat housing 7 Remove thermostat housing mounting bolts thermostat housing gasket and thermostat Fig 46 Discard old gasket COOLING SYSTEM 7 33 J9207 14 Fig 46 Thermostat 5 2L 5 9L Engines 1 THERMOSTAT HOUSING 2 GASKET 3 INTAKE MANIFOLD 4 THERMOSTAT 5 MACHINED GROOVE INSTALLATION 1 Clean mating areas of intake manifold and thermostat housing 2
6. 14 Check and correct as necessary Refer to Group 5 Brakes for correct procedures 15 Remove bug screen or cardboard 16 Check thermostat operation and replace as necessary Refer to Thermostats in this Group 17 Check fan drive operation and replace as necessary Refer to Viscous Fan Drive in this Group 18 Check for cylinder head gasket leaks Refer to Cooling System Testing For Leaks in this Group For repair refer to Group 9 Engines 19 Check heater core for leaks Refer to Group 24 Heating and Air Conditioning Repair as necessary DN DIAGNOSIS AND TESTING Continued CONDITION POSSIBLE CAUSES COOLING SYSTEM 7 13 CORRECTION TEMPERATURE GAUGE READING IS INCONSISTENT FLUCTUATES CYCLES OR IS ERRATIC 1 During cold weather operation with the heater blower in the high position the gauge reading may drop slightly 2 Temperature gauge or engine mounted gauge sensor defective or shorted Also corroded or loose wiring in this circuit 3 Gauge reading rises when vehicle is brought to a stop after heavy use engine still running 4 Gauge reading high after re starting a warmed up hot engine 5 Coolant level low in radiator air will build up in the cooling system causing the thermostat to open late 6 Cylinder head gasket leaking allowing exhaust gas to enter cooling system causing a thermostat to open late 7 Water pump impeller loose on shaft 8 Loose accessory drive b
7. 3 Remove two mounting bolts and ignition coil from engine Fig 61 4 Remove mounting bolt and tensioner assembly from engine Fig 61 WARNING BECAUSE OF HIGH SPRING PRES SURE DO NOT ATTEMPT TO DISASSEMBLE AUTO MATIC TENSIONER UNIT IS SERVICED AS AN ASSEMBLY EXCEPT FOR PULLEY 5 Remove pulley bolt Remove pulley from ten sioner INSTALLATION 1 Install pulley and pulley bolt to tensioner Tighten bolt to 61 N m 45 ft Ibs 2 Position tensioner assembly and install mount ing screw tighten screw to 67 N m 50 ft Ibs 7 40 COOLING SYSTEM REMOVAL AND INSTALLATION Continued 80be4d0c Fig 61 Automatic Belt Tensioner Removal Installation 5 2L 5 9L Engines 1 AUTOMATIC TENSIONER 2 COIL AND BRACKET 3 SCREW AND WASHER 3 Connect all wiring to ignition coil 4 Position coil to tensioner assembly install two mounting screws Tighten to 11 N m 100 in Ibs Fig 61 CAUTION To prevent damage to coil case coil mounting bolts must be torqued 5 Install accessory drive belt AUTOMATIC BELT TENSIONER 4 7L ENGINE On 4 7L engines the tensioner is equipped with an indexing tang on back of tensioner and an indexing stop on tensioner housing If a new belt is being installed tang must be within approximately 24 mm 94 inches of indexing stop Belt is considered new if it has been used 15 minutes or less If the above specification cannot be met check for e The wrong
8. 54 1 Position isolator pins into alignment holes in radiator lower support 2 Install and tighten radiator mounting bolts to 23 N m 200 in Ibs Fig 54 3 Install the transmission oil cooler lines if equipped 4 Install front grille 5 Connect fan motor electrical connector to har ness connector 6 Position upper fan shroud onto lower fan shroud and radiator 7 Install retaining screws into shroud 8 Install radiator hoses reconnect reserve overflow tank hose 9 Connect battery negative cable cooler lines if coolant DN 80bc4di8 Fig 52 Radiator Upper Fan Shroud Removal Installation Typical 1 RADIATOR 2 ELECTRIC COOLING FAN 3 UPPER SHROUD AND OVERFLOW BOTTLE 4 SCREW 5 LOWER SHROUD 80bfe1 8b Fig 53 Transmission Oil Cooler Lines Automatic Transmission Only 1 TRANSMISSION COOLER SUPPLY LINE 2 TRANSMISSION OIL COOLER RETURN LINE 10 Fill cooling system Refer to Draining and Filling Cooling System in this section 11 Start and warm the engine Check for leaks DN REMOVAL AND INSTALLATION Continued 80bce9a5 Fig 54 Radiator Removal Installation Typical 1 CORE SUPPORT 2 LOWER ISOLATOR MOUNTS 3 ISOLATOR PINS 4 RADIATOR ASSEMBLY 5 SCREWS BLOCK HEATER REMOVAL 1 Disconnec negative battery cable from battery 2 Drain coolant from radiator and cylinder block Refer to Draining Cooling Sys
9. LEVEL CHECK ds rri oi atio eos COOLING SYSTEM DRAINING AND COOLING SYSTEM CLEANING REVERSE FLUSHING aoa REMOVAL AND INSTALLATION COOLANT RESERVE OVERFLOW TANK WATER PUMP 5 2L 5 9L ENGINES WATER PUMP 4 7L ENGINES WATER PUMP BYPASS HOSE 5 2L 5 9L ENGINES 2 sicura Utt docti t ed THERMOSTAT 5 2L 5 9L ENGINE THERMOSTAT 4 7L ENGINE RADIATOR BLOCK HEATER ACCESSORY DRIVE BELT 5 2L 5 9L ENGINE crrikavrtaveereteig Ped rs pera ACCESSORY BELT REPLACEMENT 4 7L ENGINE aca Severe at Gate icr d ce wl ace oe ndo AUTOMATIC BELT TENSIONER 5 2L 5 9L ENGINE 2 i ahi nacht Nabe ca MI RR and AUTOMATIC BELT TENSIONER 4 7L ENGINE PC RADIATOR DRAINCOCK ssssssssse VISCOUS FAN DRIVE 000 ee CLEANING AND INSPECTION RADIATOR CAP RADIATOR WATER PUMP FAN BLADE sari n ls afa do ay we a SPECIFICATIONS COOLING SYSTEM CAPACITIES COOLING SYSTEM 2 55k ERE RR SPECIAL TOOLS COOLING 7 2 COOLING SYSTEM DESCRIPTION AND OPERATION COOLING SYSTEM DESCRIPTION The cooling system consists of e Radiator e Cooling fan mechanical Electrical e Thermal viscous fan drive e Fan shroud e Radiator pressure cap e Thermostat e Coolant reserve overflow system integral to upper fan shroud e Transmission oil cooler if equipped with an automatic transmission e Coolant e Water pump e Hoses and hose clamps OPERATION The cooling system regulates
10. Refer to On Board Diagnostics in Group 25 Emission Control Systems for more information on accessing a DTC The DTC can also be accessed through the DRB scan tool Refer to the appropriate Powertrain Diag 1 Level changes are to be expected as coolant volume fluctuates with engine temperature If the level in the tank was between the FULL and ADD marks at normal operating temperature the level should return to within that range after operation at elevated temperatures 1 A normal condition No repair is necessary nostic Procedures manual for diagnostic information and operation of the DRB scan tool RADIATOR FAN MOTOR INOPERATIVE Equipment Required e DRB Scan Tool e Volt Ohm meter e Wiring Diagrams section of this manual 7 16 COOLING SYSTEM DIAGNOSIS AND TESTING Continued 80be44ae Fig 19 Electrical Cooling Fan 1 RADIATOR 2 ELECTRIC FAN ASSEMBLY 3 FAN SHROUD LOWER 4 SCREW Test Procedure 1 Inspect 10A fuse in junction block and 40A maxi fuse in PDC Fig 20 2 Remove Cooling Fan Relay from the PDC and make the following checks at the relay connector e Apply 12 volts using a fused 14 gauge wire to circuit C25 relay terminal 87 If fan does not come on check for open in circuit C25 or Z1 If circuits are o k replace the cooling fan motor e With the ignition key off check for battery volt age at circuit C28 relay terminal 30 If no battery voltage prese
11. WRENCH WITH ADAPTER PINS 8346 2 FAN WARNING CONSTANT TENSION HOSE CLAMPS ARE USED ON MOST COOLING SYSTEM HOSES WHEN REMOVING OR INSTALLING USE ONLY TOOLS DESIGNED FOR SERVICING THIS TYPE OF CLAMP SUCH AS SPECIAL CLAMP TOOL NUMBER 6094 SNAP ON CLAMP TOOL NUMBER HPC 20 MAY BE USED FOR LARGER CLAMPS ALWAYS WEAR SAFETY GLASSES WHEN SERVICING CON STANT TENSION CLAMPS CAUTION A number or letter is stamped into the tongue of constant tension clamps If replacement is necessary use only an original equipment clamp with matching number or letter 4 If water pump is being replaced do not unbolt fan blade assembly from thermal viscous fan drive 5 Remove two fan shroud to radiator screws Fig 34 Disconnect the coolant overflow hose windshield washer fluid hose and washer pump electrical con nector 6 Remove upper fan shroud and fan blade viscous fan drive assembly from vehicle 7 After removing fan blade viscous fan drive assembly do not place thermal viscous fan drive in horizontal position If stored horizontally silicone fluid in viscous fan drive could drain into its bearing assembly and contaminate lubricant DN 5 80be44aa Fig 34 Upper Fan Shroud Coolant reservoir and Washer Fluid Reservoir 1 RADIATOR 2 WASHER FLUID RESERVOIR 3 COOLANT OVERFLOW RESERVOIR 4 FAN SHROUD UPPER 5 SCREW 6 INTERLOCKING PINS 7 FAN SHROUD LOWER 8 Remove accessory drive
12. belt as follows The drive belt is equipped with a spring loaded automatic belt tensioner Relax tension from belt by rotating tensioner clockwise as viewed from front Fig 35 When all belt tension has been relaxed remove accessory drive belt 9 Remove lower radiator hose damp and remove lower hose at water pump 10 Remove seven water pump mounting bolts and one stud bolt CAUTION Do not pry water pump at timing chain case cover The machined surfaces may be dam aged resulting in leaks 11 Remove water pump and gasket Discard gas ket INSTALLATION 1 Clean gasket mating surfaces 2 Using a new gasket position water pump and install mounting bolts as shown Fig 36 Tighten water pump mounting bolts to 54 N m 40 ft Ibs torque 3 Spin water pump to be sure that pump impel ler does not rub against timing chain case cover 4 Connect radiator lower hose to water pump 5 Relax tension from belt tensioner Fig 35 Install drive belt DN REMOVAL AND INSTALLATION Continued jus e Eg jh C 80b898b0 Fig 35 Automatic Belt Tensioner 4 7L 1 AUTOMATIC TENSIONER 2 WATER PUMP PULLEY l y B NE j C lt gt AT 77 INDICATES STUD LOCATION 805898b1 Fig 36 Water Pump Installation 4 7L 1 WATER PUMP 2 TIMING CHAIN COVER CAUTION When installing the serpentine acces sory drive belt belt must be routed cor
13. heater hose and hose clamp to coolant return tube 9 Relax tension from belt tensioner Fig 30 Install accessory drive belt DN REMOVAL AND INSTALLATION Continued 9307 34 Fig 31 Coolant Return Tube 5 2L 5 9L Engines Typical 1 COOLANT RETURN TUBE 2 WATER PUMP 3 TUBE MOUNTING BOLT 4 O RING CAUTION When installing the serpentine acces Sory drive belt the belt must be routed correctly If not engine may overheat due to water pump rotat ing in wrong direction Refer to Fig 32 for correct belt routing The correct belt with correct length must be used 10 Position fan shroud and fan blade viscous fan drive assembly to vehide as a complete unit 11 Install fan shroud 12 Install fan blade viscous fan drive assembly to water pump shaft 13 Fill cooling system Refer to Cooling System Draining and Refilling in this group 14 Connect battery negative cable 15 Start and warm the engine Check for leaks WATER PUMP 4 7L ENGINES The water pump on 4 7L engines is bolted directly to the engine timing chain case cover A gasket is used as a seal between the water pump and timing chain case cover If water pump is replaced because of bearing shaft damage or leaking shaft seal the mechanical cooling fan assembly should also be inspected Inspect for fatigue cracks loose blades or loose rivets that could have resulted from excessive vibration Replace fan if 7 2
14. is equipped with an indexing arrow on back of tensioner and an indexing mark on ten sioner housing If a new belt is being installed arrow must be within approximately 3 mm 1 8 in of indexing mark Belt is considered new if it has been used 15 minutes or less If this specification cannot be met check for e The wrong belt being installed incorrect length width e Worn bearings on an engine accessory A C com pressor power steering pump water pump idler pul ley or generator e A pulley on an engine accessory being loose e Misalignment of an engine accessory e Belt incorrectly routed Refer to Fig 58 ACCESSORY BELT REPLACEMENT 4 7L ENGINE NOTE The belt routing schematics are published from the latest information available at the time of publication If anything differs between these sche matics and the Belt Routing Label use the sche matics on Belt Routing Label This label is located in the engine compartment DN REMOVAL AND INSTALLATION Continued REMOVAL CAUTION DO NOT LET TENSIONER ARM SNAP BACK TO THE FREEARM POSITION SEVER DAM AGE MAY OCCUR TO THE TENSIONER Belt tension is not adjustable Belt adjustment is maintained by an automatic spring load belt ten sioner 1 Disconnect negative battery cable from battery 2 Rotate belt tensioner until it contacts it s stop Remove belt then slowly rotate the tensioner into the freearm position Fig 59 80b76f69
15. over idler pulley Let tensioner rotate back into place Remove wrench Be sure belt is properly seated on all pulleys 8 Fill cooling system Refer to Refilling Cooling System in this group 9 Connect battery negative cable 10 Start and warm the engine Check for leaks THERMOSTAT 4 7L ENGINE REMOVAL WARNING DO NOT LOOSEN RADIATOR DRAIN COCK WITH SYSTEM HOT AND PRESSURIZED SERIOUS BURNS FROM COOLANT CAN OCCUR Do not waste reusable coolant If solution is clean drain coolant into a clean container for reuse If thermostat is being replaced be sure that replacement is specified thermostat for vehicle model and engine type 1 Disconnect negative battery cable at battery 2 Drain cooling system Refer to Draining Cool ing System in this section IF VEHICLE IS NOT EQUIPPED WITH POWER STEERING THIS WILL BE AN IDLER PULLEY J9307 26 Fig 48 Belt Routing 5 2L 5 9L Engines 1 IDLER PULLEY 2 GENERATOR PULLEY 3 A C COMPRESSOR PULLEY 4 IF WOUT A C 5 POWER STEERING PUMP PULLEY 6 WATER PUMP PULLEY 7 CRANKSHAFT PULLEY 8 AUTOMATIC TENSIONER 3 Raise vehicle on hoist 4 Remove splash shield 5 Remove lower radiator hose clamp and lower radiator hose at thermostat housing 6 Remove thermostat housing mounting bolts thermostat housing and thermostat Fig 49 INSTALLATION 1 Clean mating areas of timing chain cover and thermostat housing 2 Install therm
16. overheating are e Idle with A C off when temperature gauge is at end of normal range e Increase engine speed for more air flow is recom mended 1 TRAILER TOWING Consult Trailer Towing section of owners manual Do not exceed limits 2 AIR CONDITIONING ADD ON OR AFTER MARKET A maximum cooling package should have been ordered with vehicle if add on or after market A C is installed If not maximum cooling system compo nents should be installed for model involved per manufacturer s specifications 3 RECENT SERVICE OR ACCIDENT REPAIR Determine if any recent service has been per formed on vehicle that may effect cooling system This may be e Engine adjustments incorrect timing e Slipping engine accessory drive belt s e Brakes possibly dragging e Changed parts Incorrect water pump or pump rotating in wrong direction due to belt not correctly routed e Reconditioned radiator or cooling system refill ing possibly under filled or air trapped in system NOTE If investigation reveals none of the previous items as a cause for an engine overheating com plaint refer to following Cooling System Diagnosis charts These charts are to be used as a quick reference only Refer to the group text for information DN DIAGNOSIS AND TESTING Continued COOLING SYSTEM DIAGNOSIS CHART CONDITION POSSIBLE CAUSES COOLING SYSTEM 7 11 CORRECTION TEMPERATURE GAUGE READS LOW 1 Has a Diagnostic Trouble Code
17. waste reusable coolant If solution is clean drain coolant into a clean container for reuse If thermostat is being replaced be sure that replacement is specified thermostat for vehicle model and engine type Factory installed thermostat housings on 5 2L 5 9L engines are installed on a gasket with an anti stick coating This will aid in gasket removal and clean up 1 Disconnect negative battery cable at battery 2 Drain cooling system until coolant level is below thermostat Refer to Draining Cooling System in this group 3 Air Conditioned vehicles Remove support bracket generator mounting bracket to intake mani fold located near rear of generator Fig 44 80bc4d0d Fig 44 Generator Support Bracket 5 2L 5 9L Engine 1 IDLER PULLEY BUSHING 2 A C AND OR GENERATOR MOUNTING BRACKET 3 IDLER PULLEY 4 SCREW AND WASHER 4 On air conditioning equipped vehicles the gen erator must be partially removed a Remove generator drive belt as follows Drive belts on 5 2L 5 9L engines are equipped with a spring loaded automatic belt tensioner Fig 45 b Attach a socket wrench to pulley mounting bolt of automatic tensioner Fig 45 c Rotate tensioner assembly clockwise as viewed from front until tension has been relieved from belt d Remove belt from vehide e Remove two generator mounting bolts Do not remove any wiring at generator If equipped DN REMOVAL AND INSTALLATION Continued
18. 7 COOLING SYSTEM IF VEHICLE IS NOT EQUIPPED WITH POWER STEERING THIS WILL BE AN IDLER PULLEY J9307 26 Fig 32 Belt Routing 5 2L 5 9L Engines 1 IDLER PULLEY 2 GENERATOR PULLEY 3 A C COMPRESSOR PULLEY 4 IF WOUT A C 5 POWER STEERING PUMP PULLEY 6 WATER PUMP PULLEY 7 CRANKSHAFT PULLEY 8 AUTOMATIC TENSIONER any of these conditions are found Also check condi tion of the thermal viscous fan drive Refer to Viscous Fan Drive in this group The water pump can be removed without discharg ing the air conditioning system if equipped REMOVAL 1 Disconnect negative battery cable from battery 2 Drain cooling system Refer to Draining Cool ing System in this group Do not waste reusable coolant If solution is clean drain coolant into a clean container for reuse 3 The thermal viscous fan drive is attached threaded to the water pump hub shaft Remove fan viscous fan drive assembly from water pump by turn ing mounting nut counterclockwise as viewed from front Threads on viscous fan drive are RIGHT HAND Using special tool spanner wrench 6958 with adapter pins 8346 and a suitable fan wrench loosen the fan drive Fig 33 Do not attempt to remove fan viscous fan drive assembly from vehicle at this time 7 28 COOLING SYSTEM REMOVAL AND INSTALLATION Continued c ANAT LWA 80b6b293 Fig 33 Viscous Fan and Fan Drive 4 7L 1 SPECIAL TOOL 6958 SPANNER
19. ANK CYL BLOCK 7 COOLANT TEMP SENSOR OPERATION The coolant reserve overflow system works in con junction with the radiator pressure cap It utilizes thermal expansion and contraction of coolant to keep coolant free of trapped air It provides a volume for expansion and contraction of coolant It also provides a convenient and safe method for checking coolant level and adjusting level at atmospheric pressure This is done without removing the radiator pressure cap The system also provides some reserve coolant to the radiator to cover minor leaks and evaporation or boiling losses As the engine cools a vacuum is formed in the cooling system of both the radiator and engine Cool ant will then be drawn from the coolant tank and returned to a proper level in the radiator THERM OSTAT 5 2L 5 9L ENGINES DESCRIPTION CAUTION Do not operate an engine without a ther mostat except for servicing or testing The thermostat on all gas powered engines is located beneath the thermostat housing at the front of the intake manifold Fig 4 The thermostat is a wax pellet driven reverse pop pet choke type Coolant leakage into the pellet container will cause the thermostat to fail in the open position Thermo stats very rarely stick Do not attempt to free a ther mostat with a prying device 7 4 COOLING SYSTEM DESCRIPTION AND OPERATION Continued 80be44aa Fig 3 Upper Fan Shroud with Integral Coolant Reserve Overflo
20. DITION POSSIBLE CAUSES DN CORRECTION LONGITUDAL BELT CRACKING GROOVE JUMPING Belt does not maintain correct position on pulley 1 Belt has mistracked from pulley groove 2 Pulley groove tip has worn away rubber to tensile member 1 Incorrect belt tension 2 Pulley s not within design tolerance 3 Foreign object s in grooves 4 Pulley misalignment 5 Belt cordline is broken 1 Replace belt 2 Replace belt 1 Inspect Replace tensioner if necessary 2 Replace pulley s 3 Remove foreign objects from grooves 4 Align component 5 Replace belt BELT BROKEN Note Identify and correct problem before new belt is installed 1 Incorrect belt tension 2 Tensile member damaged during belt installation 3 Severe misalignment 4 Bracket pulley or bearing failure 1 Replace Inspect Replace tensioner if necessary 2 Replace belt 3 Align pulley s 4 Replace defective component and belt NOISE Objectionable squeal squeak or rumble is heard or felt while drive belt is in operation 1 Incorrect belt tension 2 Bearing noise 3 Belt misalignment 4 Belt to pulley mismatch 5 Driven component induced vibration 1 Inspect Replace tensioner if necessary 2 Locate and repair 3 Align belt pulley s 4 Install correct belt 5 Locate defective driven component and repair TENSION SHEETING FABRIC FAILURE Woven fabric on outside circumference of belt has
21. DN COOLING SYSTEM 7 COOLING SYSTEM TABLE OF CONTENTS page DESCRIPTION AND OPERATION COOLING SYSTEM oered coma dock ar bos 2 COOLANT RESERVE OVERFLOW SYSTEM 2 THERMOSTAT 5 2L 5 9L ENGINES 3 THERMOSTAT 4 7L ENGINE 4 RADIATOR PRESSURE CAP rry n 4 RADIATOR ire a ore Rr C RR e e i 5 WATER PUMP sameie atua es deew er yon n 5 WATER PUMP BYPASS 4 7L 4 6 WATER PUMP BYPASS HOSE 5 2L 5 9L ENGINES S 43 ia Your d ed Po crant ae d dol 7 AUTOMATIC TRANSMISSION OIL COOLERS 7 AUTOMATIC BELT TENSIONER 7 BLOCK HEATER a iion Roo ROC CR ee 8 HOSE CLAMPS acs nu ick bey ECCE I e eos 8 VISCOUS FAN DRIVE bx n 9 DIAGNOSIS AND TESTING ON BOARD DIAGNOSTICS OBD 10 DRB SCAN TOOL ia uiris etae 4o ede a 10 PRELIMINARY CHECKS d ek n ais 10 ELECTRIC COOLING FAN 2 ucc arr bs 15 RADIATOR COOLANT FLOW CHECK 16 COOLING SYSTEM TESTING FOR LEAKS 16 VISCOUS FAN DBIVE 3 2e wi iate 18 ACCESSORY DRIVE BELT DIAGNOSIS 19 THERMOSTAT GAS ENGINES 21 RADIATOR CAP TO FILLER NECK SEAL PRESSURE RELIEF CHECK 21 RADIATOR CAP PRESSURE TESTING 21 COOLANT LOW LEVEL AERATION 22 COOLING SYSTEM DEAERATION 22 SERVICE PROCEDURES COOLANT ROUTINE LEVEL CHECK 22 COOLANT SERVICE 55x35 xxxn In 22 COOLANT P 22 COOLANT SELECTION AND ADDITIVES 23 COOLANT ADDING ADDITIONAL COOLANT
22. Fig 59 Belt Routing 4 7L 1 GENERATOR PULLEY 2 ACCESSORY DRIVE BELT 3 POWER STEERING PUMP PULLEY 4 CRANKSHAFT PULLEY 5 IDLER PULLEY 6 TENSIONER 7 A C COMPRESSOR PULLEY 8 WATER PUMP PULLEY INSTALLATION Belt tension is not adjustable Belt adjustment is maintained by an automatic spring load belt ten sioner 1 Check condition of all pulleys CAUTION When installing the serpentine acces sory drive belt the belt MUST be routed correctly If not the engine may overheat due to the water pump rotating in the wrong direction Fig 59 COOLING SYSTEM 7 39 2 Install new belt Fig 59 Route the belt around all pulleys except the idler pulley Rotate the tensioner arm until it contacts it s stop position Route the belt around the idler and slowly let the tensioner rotate into the belt Make sure the belt is seated onto all pulleys 3 With the drive belt installed inspect the belt wear indicator Fig 60 On 4 7L Engines only the gap between the tang and the housing stop mea surement A must not exceed 24 mm 94 inches If the measurement exceedes this specification replace the serpentine accessory drive belt 80ba780b Fig 60 Accessory Drive Belt Wear Indicator 4 7L Engine 1 AUTOMATIC TENSIONER ASSEMBLY AUTOMATIC BELT TENSIONER 5 2L 5 9L ENGINE REMOVAL 1 Remove accessory drive belt 2 Disconnect wiring and secondary cable from ignition coil
23. H AS SPECIAL CLAMP TOOL NUMBER 6094 Fig 50 SNAP ON CLAMP TOOL NUMBER HPC 20 MAY BE USED FOR LARGER CLAMPS ALWAYS WEAR SAFETY GLASSES WHEN SERVIC ING CONSTANT TENSION CLAMPS CAUTION A number or letter is stamped into the tongue of constant tension clamps Fig 51 If replacement is necessary use only an original equipment clamp with matching number or letter J9207 36 Fig 50 Hose Clamp Tool Typical 1 HOSE CLAMP TOOL 6094 2 HOSE CLAMP 7 36 COOLING SYSTEM REMOVAL AND INSTALLATION Continued 80bdbd2b Fig 51 Clamp Number Letter Location 1 CONSTANT TENSION HOSE CLAMP 2 CLAMP NUMBER LETTER LOCATION 3 HOSE 3 Remove hose damps Fig 50 and hoses from radiator Disconnect coolant reserve overflow tank hose and washer bottle electrical connector and hose 4 Remove upper fan shroud mounting screws Lift upper fan shroud assembly up and out of engine com partment Fig 52 5 Remove front grille Refer to BODY for proce dure 6 Disconnect transmission oil equipped Fig 53 7 Disconnec electric cooling fan motor connector 8 Remove radiator upper mounting screws Fig 54 Lift radiator upward and away from vehicle Do not allow cooling fins of radiator to contact any other vehicle component Radiator fin damage could result INSTALLATION The radiator has two isolator pins on bottom of both tanks These fit into alignment holes in radiator lower support Fig
24. ION Continued AN TURN CLOCKWISE TO REMOVE BELT Fig 57 Automatic Belt Tensioner Belt Removal Installation 1 IDLER PULLEY 2 TENSIONER 3 FAN BLADE 1 Attach a socket wrench to pulley mounting bolt of automatic tensioner Fig 57 2 Rotate tensioner assembly clockwise as viewed from front until tension has been relieved from belt 3 Remove belt from idler pulley first 4 Remove belt from vehicle INSTALLATION CAUTION When installing serpentine accessory drive belt the belt must be routed correctly If not engine may overheat due to water pump rotating in wrong direction Refer to Fig 58 for correct engine belt routing The correct belt with correct length must be used 1 Position drive belt over all pulleys except idler pulley This pulley is located between generator and A C compressor 2 Attach a socket wrench to pulley mounting bolt of automatic tensioner Fig 57 3 Rotate socket wrench clockwise Place belt over idler pulley Let tensioner rotate back into place Remove wrench Be sure belt is properly seated on all pulleys 4 Check belt indexing marks Refer to Automatic Belt Tensioner 5 2L 5 9L for more belt information DN 80bo4ffe Fig 58 Belt Routing 5 2L 5 9L Engine 1 TENSIONER 2 GENERATOR PULLEY 3 IDLER PULLEY 4 A C COMPRESSOR PULLEY 5 WATER PUMP PULLEY 6 POWER STEERING PUMP PULLEY 7 CRANKSHAFT PULLEY The tensioner
25. Inspect cooling fins to make sure they are not bent or crushed these areas result in reduced heat exchange causing the cooling system to operate at higher temperatures Inspect the plastic end tanks for cracks damage or leaks Inspect the radiator neck for damage or distortion WATER PUMP CLEANING Clean the gasket mating surface Use caution not to damage the gasket sealing surface INSPECTION Inspect the water pump assembly for cracks in the housing Water leaks from shaft seal Loose or rough turning bearing or Impeller rubbing either the pump body or timing chain case cover FAN BLADE CLEANING Clean the fan blades using a mild soap and water Do not use an abrasive to clean the blades COOLING SYSTEM 7 43 INSPECTION WARNING DO NOT ATTEMPT TO BEND OR STRAIGHTEN FAN BLADES IF FAN IS NOT WITHIN SPECIFICATIONS CAUTION If fan blade assembly is replaced because of mechanical damage water pump and viscous fan drive should also be inspected These components could have been damaged due to excessive vibration 1 Remove fan blade assembly from viscous fan drive unit four bolts 2 Lay fan on a flat surface with leading edge fac ing down With tip of blade touching flat surface replace fan if clearance between opposite blade and surface is greater than 2 0 mm 090 inch Rocking motion of opposite blades should not exceed 2 0 mm 090 inch Test all blades in this manner 3 Inspect fan assembly for crack
26. M COOLANT CAN OCCUR 1 Unscrew draincock stem counterclockwise rotation When stem is completely unscrewed pull it from radiator tank and draincock body Fig 63 DN REMOVAL AND INSTALLATION Continued RRO7BS5O Fig 63 Draincock Assembly 1 BODY 2 SEAL 3 STEM 2 Using a pair of needle nose pliers compress draincock body and pull straight out of radiator Fig 64 RRO7B51 Fig 64 Draincock Body Removal 1 DRAINCOCK BODY 2 NEEDLE NOSE PLIERS INSTALLATION 1 Install draincock stem loosely into body Fig 65 The draincock assembly cannot be installed if stem is threaded into the body 2 Push draincock assembly into opening in radi ator tank It will snap into place when fully seated 3 Tighten draincock clockwise to 2 0 to 2 7 N m 18 25 in lbs torque COOLING SYSTEM 7 41 Fig 65 Draincock Assembled for Installation 1 STEM 2 BODY LOOSE ON STEM RRO7B27 VISCOUS FAN DRIVE REM OVAL 1 Disconnect battery negative cable 2 The thermal viscous fan drive fan blade assem bly is attached threaded to water pump hub shaft Fig 67 Remove fan blade viscous fan drive assem bly from water pump by turning mounting nut coun terdockwise as viewed from front Threads on viscous fan drive are RIGHT HAND A Snap On 36 MM Fan Wrench number SP346 from Snap On Cummins Diesel Tool Set number 2017DSP and Spe cial Tool 6958 Spanner Wrenc
27. NT LOSS TO THE GROUND WITHOUT PRESSURE CAP BLOWOFF GAUGE READING HIGH OR HOT 1 Coolant leaks in radiator cooling system hoses water pump or engine 1 Pressure test and repair as necessary Refer to Cooling System Testing For Leaks in this group 7 14 COOLING SYSTEM DIAGNOSIS AND TESTING Continued CONDITION POSSIBLE CAUSES DN CORRECTION DETONATION OR PRE IGNITION NOT CAUSED BY IGNITION SYSTEM GAUGE MAY OR MAY NOT BE READING HIGH 1 Engine overheating 2 Freeze point of coolant not correct Mixture is too rich or too lean 1 Check reason for overheating and repair as necessary 2 Check coolant concentration Refer to the Coolant section of this group and adjust ratio as required HOSE OR HOSES COLLAPSE WHILE ENGINE IS RUNNING 1 Vacuum created in cooling system on engine cool down is not being relieved through coolant reserve overflow system 1 a Radiator cap relief valve stuck Refer to Radiator Cap in this group Replace if necessary b Hose between coolant reserve overflow tank and radiator is kinked Repair as necessary c Vent at coolant reserve overflow tank is plugged Clean vent and repair as necessary d Reserve overflow tank is internally blocked or plugged Check for blockage and repair as necessary NOISY VISCOUS FAN DRIVE 1 Fan blades loose 2 Fan blades striking a surrounding object 3 Air obstructions at radiator or air cond
28. RNING CONSTANT TENSION HOSE CLAMPS ARE USED ON MOST COOLING SYSTEM HOSES WHEN REMOVING OR INSTALLING USE ONLY TOOLS DESIGNED FOR SERVICING THIS TYPE OF CLAMP SUCH AS SPECIAL CLAMP TOOL NUMBER 6094 Fig 38 SNAP ON CLAMP TOOL NUMBER HPC 20 MAY BE USED FOR LARGER CLAMPS ALWAYS WEAR SAFETY GLASSES WHEN SERVIC ING CONSTANT TENSION CLAMPS CAUTION A number or letter is stamped into the tongue of constant tension clamps Fig 39 If replacement is necessary use only an original equipment clamp with matching number or letter J9207 36 Fig 38 Hose Clamp Tool Typical 1 HOSE CLAMP TOOL 6094 2 HOSE CLAMP 2 Loosen both bypass hose clamps Fig 38 and position to center of hose Remove hose from vehicle INSTALLATION 1 Position bypass hose clamps Fig 38 to center of hose 2 Install bypass hose to engine 3 Secure both hose clamps Fig 38 4 Fill cooling system 5 Start and warm the engine Check for leaks DN 80bdbd2b Fig 39 Clamp Number Letter Location 1 CONSTANT TENSION HOSE CLAMP 2 CLAMP NUMBER LETTER LOCATION 3 HOSE REMOVAL WITH AIR CONDITIONING If equipped with A C the generator and A C com pressor along with their common mounting bracket Fig 40 must be partially removed Removing gener ator or A C compressor from their mounting bracket is not necessary Also discharging A C system is not necessary Do not remove any refrigerant lines from A C co
29. VEL AERATION If the coolant level in the radiator drops below the top of the radiator core tubes air will enter the sys tem Low coolant level can cause the thermostat pellet to be suspended in air instead of coolant This will cause the thermostat to open later which in turn causes higher coolant temperature Air trapped in cooling system also reduces the amount of coolant circulating in the heater core This may result in low heat output COOLING SYSTEM DEAERATION As the engine operates any air trapped in cooling system gathers under the radiator cap The next time the engine is operated thermal expansion of coolant will push any trapped air past radiator cap into the coolant reserve overflow tank Here it escapes to the atmosphere into the tank When the engine cools down the coolant it will be drawn from the reserve overflow tank into the radiator to replace any removed air SERVICE PROCEDURES COOLANT ROUTINE LEVEL CHECK NOTE Do not remove radiator cap for routine cool ant level inspections The coolant level can be checked at coolant recovery bottle Fig 25 The coolant reserve overflow system provides a quick method for determining coolant level without removing radiator pressure cap With engine not run ning open the coolant recovery bottle cap and remove coolant level indicator dipstick to observe coolant level in coolant recovery bottle The coolant level should be between ADD and FULL marks If the cool
30. VERFLOW TANK SQUEEZE RADIATOR UPPER HOSE TO DETERMINE WHEN PRESSURE HAS BEEN RELEASED WHEN COOLANT AND STEAM STOP BEING PUSHED INTO TANK AND SYSTEM PRES SURE DROPS REMOVE RADIATOR CAP COM PLETELY RADIATOR CAP PRESSURE TESTING Remove cap from radiator Be sure that sealing surfaces are clean Moisten rubber gasket with water and install cap on pressure tester 7700 or an equiv alent Fig 24 J9507 3 Fig 24 Pressure Testing Radiator Cap Typical 1 PRESSURE CAP 2 TYPICAL COOLING SYSTEM PRESSURE TESTER Operate tester pump to bring pressure to 117 kPa 17 psi on gauge If pressure cap fails to hold pres sure of at least 110 kPa 16 psi replace cap Refer to following CAUTION The pressure cap may test properly while posi tioned on tool 7700 or equivalent It may not hold pressure or vacuum when installed on radiator If so inspect radiator filler neck and cap s top gasket for damage Also inspect for dirt or distortion that may prevent cap from sealing properly 7 22 COOLING SYSTEM DIAGNOSIS AND TESTING Continued CAUTION Radiator pressure testing tools are very sensitive to small air leaks which will not cause cooling system problems A pressure cap that does not have a history of coolant loss should not be replaced just because it leaks slowly when tested with this tool Add water to tool Turn tool upside down and recheck pressure cap to confirm that cap needs replacement COOLANT LOW LE
31. abs Wipe inside of filler neck and examine lower inside sealing seat for nicks cracks paint dirt and solder residue Inspect radia tor to reserve overflow tank hose for internal obstructions Insert a wire through the hose to be sure it is not obstructed Inspect cams on outside of filler neck If cams are damaged seating of pressure cap valve and tester seal will be affected Attach pressure tester 7700 or an equivalent to radiator filler neck Fig 22 Operate tester pump to apply 103 4 kPa 15 psi pressure to system If hoses enlarge excessively or bulges while testing replace as necessary Observe COOLING SYSTEM 7 17 19507 2 Fig 22 Pressure Testing Cooling System Typical 1 TYPICAL COOLING SYSTEM PRESSURE TESTER gauge pointer and determine condition of cooling sys tem according to following criteria Holds Steady If pointer remains steady for two minutes serious coolant leaks are not present in sys tem However there could be an internal leak that does not appear with normal system test pressure If it is certain that coolant is being lost and leaks can not be detected inspect for interior leakage or per form Internal Leakage Test Drops Slowly Indicates a small leak or seepage is occurring Examine all connections for seepage or slight leakage with a flashlight Inspect radiator hoses gasket edges and heater Seal small leak holes with a Sealer Lubricant or equivalent Repair leak h
32. ad of completely blocking the flow This design controls coolant temperature more accurately Fig 5 The same thermostat is used for winter and sum mer seasons An engine should not be operated with out a thermostat except for servicing or testing Operating without a thermostat causes other prob lems These are longer engine warmup time unreli able warmup performance increased exhaust emissions and crankcase condensation This conden sation can result in sludge formation OPERATION The wax pellet is located in a sealed container at the spring end of the thermostat When heated the pellet expands overcoming dosing spring tension and water pump pressure to force the valve to open RADIATOR PRESSURE CAP DESCRIPTION All radiators are equipped with a pressure cap This cap releases pressure at some point within a range of 124 to 145 kPa 18 to 21 psi The pressure relief point in pounds is engraved on top of the cap The cooling system will operate at pressures slightly above atmospheric pressure This results in a DN DESCRIPTION AND OPERATION Continued E D THE CLOSED POSITION 80b897e4 Fig 5 Thermostat Cross Section View 4 7L 1 FROM HEATER 2 FROM RADIATOR 3 TO WATER PUMP 4 ENGINE BYPASS 5 THERMOSTAT higher coolant boiling point allowing increased radi ator cooling capadty The cap contains a spring loaded pressure relief valve This valve opens when system pressure reaches the
33. after test to eliminate boil over Start engine and accelerate rapidly three times to approximately 3000 rpm while observing coolant If internal engine combustion gases are leaking into DN cooling system bubbles will appear in coolant If bub bles do not appear internal combustion gas leakage is not present VISCOUS FAN DRIVE If the fan assembly free wheels without drag the fan blades will revolve more than five turns when spun by hand replace the fan drive This spin test must be performed when the engine is cool For the following test the cooling system must be in good condition It also will ensure against exces sively high coolant temperature WARNING BE SURE THAT THERE IS ADEQUATE FAN BLADE CLEARANCE BEFORE DRILLING 1 Drill a 3 18 mm 1 8 in diameter hole in the top center of the fan shroud 2 Obtain a dial thermometer with an 8 inch stem or equivalent It should have a range of 18 to 105 C 0 to 220 F Insert thermometer through the hole in the shroud Be sure that there is adequate clearance from the fan blades 3 Connect a tachometer and an engine ignition timing light timing light is to be used as a strobe light 4 Block the air flow through the radiator Secure a sheet of plastic in front of the radiator or air con ditioner condenser Use tape at the top to secure the plastic and be sure that the air flow is blocked 5 Be sure that the air conditioner if equipped is turned off
34. all amount of coolant from radiator until ends of radiator tubes are visible through filler neck Idle engine at normal operating temperature If coolant is flowing past exposed tubes coolant is cir culating COOLING SYSTEM TESTING FOR LEAKS ULTRAVIOLET LIGHT METHOD A leak detection additive is available through the parts department that can be added to cooling sys tem The additive is highly visible under ultraviolet light black light Pour one ounce of additive into cooling system Place heater control unit in HEAT position Start and operate engine until radiator upper hose is warm to touch Aim the commercially available black light tool at components to be DN DIAGNOSIS AND TESTING Continued checked If leaks are present black light will cause additive to glow a bright green color The black light can be used in conjunction with a pressure tester to determine if any external leaks exist Fig 21 j ci Eg p 1 E J9507 1 Fig 21 Leak Detection Using Black Light Typical 1 TYPICAL BLACK LIGHT TOOL PRESSURE TESTER METHOD The engine should be at normal operating temper ature Recheck the system cold if cause of coolant loss is not located during the warm engine examina tion WARNING HOT PRESSURIZED COOLANT CAN CAUSE INJURY BY SCALDING Carefully remove radiator pressure cap from filler neck and check coolant level Push down on cap to disengage it from stop t
35. ant level is at or below the ADD mark fill the recovery bottle with a 50 50 mixture of antifreeze and water ONE QUART AT A TIME Repeat this pro cedure until the coolant level is at the FULL mark DN 80be44aa Fig 25 Coolant Hecovery Bottle Location RADIATOR 1 2 WASHER FLUID RESERVOIR 3 COOLANT OVERFLOW RESERVOIR 4 FAN SHROUD UPPER 5 SCREW 6 INTERLOCKING PINS 7 FAN SHROUD LOWER COOLANT SERVICE For cooling system flush and fill maintenance intervals refer to Group 0 Lubrication and Mainte nance COOLANT DESCRIPTION ETHYLENE GLYCOL MIXTURES CAUTION Richer antifreeze mixtures cannot be measured with normal field equipment and can cause problems associated with 100 percent ethyl ene glycol The required ethylene gl ycol antifreeze and water mixture depends upon the climate and vehicle oper ating conditions The recommended mixture of 50 50 ethylene glycol and water will provide protection against freezing to 37 deg C 35 deg F The anti freeze concentration must always be a minimum of 44 percent year round in all climates If percentage is lower than 44 percent engine parts may be eroded by cavitation and cooling system com ponents may be severely damaged by corrosion Maximum protection against freezing is provided with a 68 percent antifreeze concentration which prevents freezing down to 67 7 deg C 90 deg F A DN SERVICE PROCEDURES Continued high
36. belt being installed incorrect length width e Worn bearings on an engine accessory A C com pressor power steering pump water pump idler pul ley or generator e A pulley on an engine accessory being loose e Misalignment of an engine accessory e Belt incorrectly routed NOTE A used belt should be replaced if tensioner indexing arrow has moved to the minmum tension indicator Tensioner travel stops at this point REM OVAL 1 Remove accessory drive belt Refer to Accessory Drive Belt in this section 2 Remove tensioner assembly from mounting bracket Fig 62 DN 80b8968fb Fig 62 Automatic Belt Tensioner 4 7L Engine 1 TIMING CHAIN COVER 2 BOLT TORQUE TO 41 N m 30 FT LBS 3 AUTOMATIC BELT TENSIONER WARNING BECAUSE OF HIGH SPRING PRES SURE DO NOT ATTEMPT TO DISASSEMBLE AUTO MATIC TENSIONER UNIT IS SERVICED AS AN ASSEMBLY EXCEPT FOR PULLEY ON TENSIONER 3 Remove pulley bolt Remove pulley from ten sioner INSTALLATION 1 Install pulley and pulley bolt to tensioner Tighten bolt to 61 N m 45 ft Ibs torque 2 An indexing slot is located on back of tensioner Align this slot to the head of the bolt on the front cover Install the mounting bolt Tighten bolt to 41 N m 30 ft Ibs 3 Install accessory drive belt 4 Check belt indexing marks RADIATOR DRAINCOCK REMOVAL WARNING DO NOT LOOSEN RADIATOR DRAIN COCK WITH SYSTEM HOT AND PRESSURIZED SERIOUS BURNS FRO
37. ble 80bc4d11 Fig 68 Viscous Fan Drive and Fan Blade 1 VISCOUS FAN DRIVE 2 FAN BLADE 3 SCREW AND WASHER 80bc4d18 Fig 69 Upper Fan Shroud Removal installation 1 RADIATOR 2 ELECTRIC COOLING FAN 3 UPPER SHROUD AND OVERFLOW BOTTLE 4 SCREW 5 LOWER SHROUD CLEANING AND INSPECTION RADIATOR CAP CLEANING Use only a mild soap and water to clean the radi ator cap Using any type solvent may cause damage to the seal in the radiator cap DN CLEANING AND INSPECTION Continued INSPECTION Hold cap at eye level right side up The vent valve Fig 29 at bottom of cap should open If rubber gas ket has swollen and prevents vent valve from open ing replace cap Hold cap at eye level upside down If any light can be seen between vent valve and rubber gasket replace cap Do not use a replacement cap that has a spring to hold vent shut A replacement cap must be the type designed for a coolant reserve over flow system with a completely sealed diaphragm spring and a rubber gasket This gasket is used to seal to radiator filler neck top surface Use of proper cap will allow coolant return to radiator RADIATOR CLEANING Clean radiator fins With the engine cold apply cold water and compressed air to the back engine side of the radiator to flush the radiator and or A C con denser of debris INSPECTION The radiator cooling fins should be checked for damage or deterioration
38. certain cooling system com ponents e f the engine has remained cool for too long a period such as with a stuck open thermostat a Diag nostic Trouble Code DTC can be set e f an open or shorted condition has developed in the relay circuit controlling the electric radiator fan a Diagnostic Trouble Code DTC can be set If the problem is sensed in a monitored circuit often enough to indicated an actual problem a DTC is stored The DTC will be stored in the PCM mem ory for eventual display to the service technician Refer to Group 25 Emission Control Systems for the correct procedures ACCESSING DIAGNOSTIC TROUBLE CODES To read DTC s and to obtain cooling system data refer to Group 25 Emission Control Systems for the correct procedures ERASING TROUBLE CODES After the problem has been repaired use the DRB scan tool to erase a DTC Refer to the appropriate Powertrain Diagnostic Procedures service manual for operation of the DRB scan tool DRB SCAN TOOL For operation of the DRB scan tool refer to the appropriate Powertrain Diagnostic Procedures ser vice manual PRELIMINARY CHECKS ENGINE COOLING SYSTEM OVERHEATING Establish what driving conditions caused the com plaint Abnormal loads on the cooling system such as the following may be the cause DN PROLONGED IDLE VERY HIGH AMBIENT TEMPERATURE SLIGHT TAIL WIND AT IDLE SLOW TRAFFIC TRAFFIC JAMS HIGH SPEED OR STEEP GRADES Driving techniques that avoid
39. d position the bypass gallery is not obstructed allowing 10096 flow When the thermostat is in the open position the stub shaft enters the bypass gallery obstructing bypass coolant flow by 5096 This design allows the coolant to reach operating temperature quickly when cold while adding extra cooling during normal tempera ture operation DN DESCRIPTION AND OPERATION Continued WATER PUMP BYPASS HOSE 5 2L 5 9L ENGINES DESCRIPTION A rubber water pump bypass hose Fig 10 is used between the intake manifold and water pump on all 5 2L 5 9L engines 80bdbd2c Fig 10 Water Pump Bypass Hose 5 2L 5 9L Engines 1 WATER PUMP BYPASS HOSE 2 FAN BLADE ASSEMBLY 3 VISCOUS FAN DRIVE 4 WATER PUMP AND PULLEY OPERATION When the thermostat is in the closed position the bypass hose allows the water pump to circulate the engine coolant through the cylinder block while at the same time preventing the coolant from flowing through the radiator this allows the coolant to heat up quicker thus bring the engine to operating tem perature faster AUTOMATIC TRANSMISSION OIL COOLERS DESCRIPTION CAUTION On in radiator type oil coolers if trans mission oil cooler is leaking engine coolant may enter cooler or transmission oil may enter engine cooling system Both engine cooling system and transmission oil circuit should be drained flushed and inspected There are two types of transmission oil coolers used One t
40. e from heater hose coolant return tube 13 Loosen heater hose coolant return tube mounting bolt Fig 31 and remove tube from water pump Discard the old tube O ring 14 Remove seven water pump mounting bolts 15 Loosen damp at water pump end of bypass hose Fig 29 Slip bypass hose from water pump while removing pump from vehicle Discard old gas ket CAUTION Do not pry water pump at timing chain case cover The machined surfaces may be dam aged resulting in leaks DN AN TURN CLOCKWISE TO REMOVE BELT Fig 30 Automatic Belt Tensioner Assembly 5 2L 5 9L Engines 1 IDLER PULLEY 2 TENSIONER 3 FAN BLADE INSTALLATION 1 Clean gasket mating surfaces 2 Using a new gasket install water pump to engine as follows Guide water pump nipple into bypass hose as pump is being installed Install water pump bolts Tighten water pump mounting bolts to 40 N m 30 ft Ibs torque 3 Position bypass hose clamp to bypass hose 4 Spin water pump to be sure that pump impel ler does not rub against timing chain case cover 5 Install a new O ring to the heater hose coolant return tube Fig 31 Coat the new O ring with anti freeze before installation 6 Install coolant return tube and its mounting bolt to engine Fig 31 Be sure the slot in tube bracket is bottomed to mounting bolt This will prop erly position return tube 7 Connect radiator lower hose to water pump 8 Connect
41. e of A C generator mounting bracket 9 Disconnect throttle body control cables Refer to ACCELERATOR PEDAL and THROTTLE CABLE in FUEL SYSTEM for procedure 10 Remove heater hose clamp and heater hose from heater hose coolant return tube 11 Remove heater hose coolant return tube mounting bolt Fig 42 and remove tube from engine Discard the old tube O ring COOLING SYSTEM y yi X y X LD 7 31 Fig 42 Coolant Return Tube 5 2L 5 9L Engines Typical 1 COOLANT RETURN TUBE 2 WATER PUMP 3 TUBE MOUNTING BOLT 4 O RING 12 Remove bracket tointake manifold bolts number 1 and 2 Fig 40 13 Remove six bracket bolts number 3 Fig 40 14 Lift and position generator and A C compres sor along with their common mounting bracket to gain access to bypass hose A block of wood may be used to hold assembly in position 15 Loosen and position both hose damps to cen ter of bypass hose Remove hose from vehicle INSTALLATION 1 Position bypass hose clamps to center of hose 2 Install bypass hose to engine 3 Secure both hose damps Fig 38 4 Install generator A C mounting bracket assem bly to engine Tighten bolts number 1 and 2 Fig 40 to 54 N m 40 ft Ibs torque Tighten bolts num ber 3 Fig 40 to 40 N m 30 ft Ibs torque 5 Install a new O ring to the heater hose coolant return tube Fig 42 Coat the new O ring with anti freeze befor
42. e installation 6 Install coolant return tube and its mounting bolt to engine Fig 42 7 Connect throttle body control cables 8 Install oil dipstick mounting bolt 7 32 COOLING SYSTEM REMOVAL AND INSTALLATION Continued 9 Install idler pulley Tighten bolt to 54 N m 40 ft Ibs torque 10 Relax tension from belt tensioner Fig 41 Install drive belt CAUTION When installing serpentine accessory drive belt the belt must be routed correctly If not engine may overheat due to water pump rotating in wrong direction Refer to Fig 43 for correct belt routing The correct belt with correct length must be used IF VEHICLE IS NOT EQUIPPED WITH POWER STEERING THIS WILL BE AN IDLER PULLEY J9307 26 Fig 43 Belt Routing 5 2L 5 9L Engines 1 IDLER PULLEY 2 GENERATOR PULLEY 3 A C COMPRESSOR PULLEY 4 IF WOUT A C 5 POWER STEERING PUMP PULLEY 6 WATER PUMP PULLEY 7 CRANKSHAFT PULLEY 8 AUTOMATIC TENSIONER 11 Install air cleaner assembly 12 Install upper radiator hose to radiator 13 Connect wiring harness to A C compressor 14 Connect battery negative cable 15 Fill cooling system Refer to Draining and Filling Cooling System in this section 16 Start and warm the engine Check for leaks DN THERM OSTAT 5 2L 5 9L ENGINE REMOVAL WARNING DO NOT LOOSEN RADIATOR DRAIN COCK WITH SYSTEM HOT AND PRESSURIZED SERIOUS BURNS FROM COOLANT CAN OCCUR Do not
43. elt water pump slipping 9 Air leak on the suction side of the water pump allows air to build up in cooling system causing thermostat to open late PRESSURE CAP IS BLOWING OFF STEAM AND OR COOLANT TO COOLANT TANK TEMPERATURE GAUGE READING MAY BE ABOVE NORMAL BUT NOT HIGH COOLANT LEVEL MAY BE HIGH IN COOLANT RESERVE OVERFLOW TANK 1 Pressure relief valve in radiator cap is defective 1 Anormal condition No correction is necessary 2 Check operation of gauge and repair if necessary Refer to Group 8E Instrument Panel and Gauges 3 A normal condition No correction is necessary Gauge should return to normal range after vehicle is driven 4 Anormal condition No correction is necessary The gauge should return to normal range after a few minutes of engine operation 5 Check and correct coolant leaks Refer to Cooling System Testing for leaks in this group 6 a Check for cylinder head gasket leaks Refer to Cooling System Testing for Leaks in this group b Check for coolant in the engine oil Inspect for white steam emitting from the exhaust system Repair as necessary 7 Check water pump and replace as necessary Refer to water Pumps in this group 8 Refer to Accessory Drive Belts in this group Check and correct as necessary 9 Locate leak and repair as necessary 1 Check condition of radiator cap and cap seals Refer to Radiator Caps in this group Replace cap as necessary COOLA
44. emove radiator pressure cap 2 Loosen radiator petcock 7 24 COOLING SYSTEM SERVICE PROCEDURES Continued 3 Place a drain pan under the thermostat hous ing then remove the thermostat housing and ther mostat 4 7L only 4 Remove cylinder block drain plugs Refer to Fig 26 Fig 27 J9307 42 Fig 26 Cylinder Block Drain Plug 5 2L 5 9L Engines Typical 1 BLOCK DRAIN PLUG 80b8990 Fig 27 Cylinder Block Drain Plug 4 7L Engine Typical 1 CYLINDER BLOCK DRAIN PLUG 2 EXHAUST MANIFOLD AND HEAT SHIELD REFILLING Clean cooling system prior to refilling Refer to Cooling System Cleaning section of this group 1 Install cylinder block drain plug s s Coat the threads with Mopar Thread Sealant with Teflon DN 2 Close radiator petcock 3 Fill cooling system with a 50 50 mixture of water and Mopar Antifreeze Coolant 4 Fill coolant reserve overflov tank to FULL mark on indicator stick 5 Start and operate engine until thermostat opens upper radiator hose warm to touch 6 If necessary add a 50 50 water and Mopar Antifreeze Coolant mixture to the coolant reserve overflow tank This is done to maintain coolant level between the FULL and ADD marks The level in the reserve overflow tank may drop below the ADD mark after three or four warm up and cool down cydes COOLING SYSTEM CLEANING REVERSE FLUSHING CLEANING Drain coo
45. ends and check for obstructions 4 Locate kinked area and repair as necessary 5 Refer to Water Pump in this group If a slipping belt is detected refer to Accessory Drive Belts in this group If heater core obstruction is detected refer to Group 24 Heating and Air Conditioning STEAM IS COMING FROM THE FRONT OF VEHICLE NEAR THE GRILL AREA WHEN WEATHER IS WET ENGINE IS WARMED UP AND RUNNING AND VEHICLE IS STATIONARY TEMPERATURE GAUGE IS IN NORMAL RANGE 1 During wet weather moisture snow ice or rain condensation on the radiator will evaporate when the thermostat opens This opening allows heated water into the radiator When the moisture contacts the hot radiator steam may be emitted This usually occurs in cold weather with no fan or airflow to blow it away 1 Occasional steam emitting from this area is normal No repair is necessary COOLANT COLOR 1 Coolant color is not necessarily an indication of adequate corrosion or temperature protection Do not rely on coolant color for determining condition of coolant 1 Refer to Coolant in this group for coolant concentration information Adjust coolant mixture as necessary COOLANT LEVEL CHANGES IN COOLANT RESERVE OVERFLOW TANK TEMPERATURE GAUGE IS IN NORMAL RANGE ELECTRIC COOLING FAN The powertrain control module PCM will set a diagnostic trouble code DTC in memory if it detects a problem in the electric cooling fan relay or circuit
46. engine operating tem perature It allows the engine to reach normal oper S BYPASS THERMOSTAT CLOSED HIGH FLOW THERMOSTAT OPEN LOW FLOW ON ating temperature as quickly as possible It also maintains normal operating temperature and pre vents overheating The cooling system also provides a means of heat ing the passenger compartment and cooling the auto matic transmission fluid if equipped The cooling system is pressurized and uses a centrifugal water pump to circulate coolant throughout the system An optional factory installed maximum duty cool ing package is available on most models This pack age will provide additional cooling capacity for vehicles used under extreme conditions such as trailer towing in high ambient temperatures COOLANT RESERVE OVERFLOW SYSTEM DESCRIPTION The coolant reserve overflow tank is integral to the upper fan shroud assembly and is made of high tem perature plastic J9407 1 Fig 1 Engine Cooling System Flow 5 2L 5 9L Engines Typical 1 HEATER 2 BYPASS 3 CROSSFLOW RADIATOR DN DESCRIPTION AND OPERATION Continued TO HEATER CORE FROM HEATER an FROM RADIATOR TO W PUMP COOLING SYSTEM 7 3 v TO RADIATOR 80b46c07 Fig 2 Engine Cooling System Flow 4 7L Engine Typical 1 LH CYL HEAD 2 BLEED 3 THERMOSTAT LOCATION 4 RH CYL HEAD 5 RH BANK CYL BLOCK 6 LH B
47. er percentage will freeze at a warmer tempera ture Also a higher percentage of antifreeze can cause the engine to overheat because the specific heat of antifreeze is lower than that of water Use of 100 percent ethylene glycol will cause for mation of additive deposits in the system as the cor rosion inhibitive additives in ethylene glycol require the presence of water to dissolve The deposits act as insulation causing temperatures to rise to as high as 149 deg C 300 deg F This temperature is hot enough to melt plastic and soften solder The increased temperature can result in engine detona tion In addition 100 percent ethylene glycol freezes at 22 deg C 8 deg F PROPYLENE GLYCOL MIXTURES It s overall effective temperature range is smaller than that of ethylene glycol The freeze point of 50 50 propylene glycol and water is 32 deg C 26 deg F 5 deg C higher than ethylene glycol s freeze point The boiling point protection against summer boil over of propylene glycol is 125 deg C 257 deg F at 96 5 kPa 14 psi compared to 128 deg C 263 deg F for ethylene glycol Use of propylene gl ycol can result in boil over or freeze up on a cooling sys tem designed for ethylene glycol Propylene glycol also has poorer heat transfer characteristics than ethylene glycol This can increase cylinder head tem peratures under certain conditions Propylene glycol ethyl ene gl ycol Mixtures can cause the destabilizati
48. er pump and attach a lead away hose to water pump inlet fitting CAUTION On vehicles equipped with a heater water control valve be sure heater control valve is closed heat off This will prevent coolant flow with scale and other deposits from entering heater core Connect water supply hose and air supply hose to flushing gun Allow engine to fill with water When engine is filled apply air in short blasts allowing system to fill between air blasts Continue until clean water flows through the lead away hose Remove lead away hose flushing gun water sup ply hose and air supply hose Remove thermostat housing and install thermostat Install thermostat housing with a replacement gasket Refer to Thermo stat Replacement Connect radiator hoses Refill cool ing system with correct antifreeze water mixture Refer to Refilling the Cooling System CHEMICAL CLEANING In some instances use a radiator cleaner Mopar Radiator Kleen or equivalent before flushing This will soften scale and other deposits and aid flushing operation CAUTION Follow manufacturers instructions when using these products REMOVAL AND INSTALLATION COOLANT RESERVE OVERFLOW TANK NOTE The coolant reservoir overflow tank is inte geral to the upper fan shroud Refer to Fan Shroud in this section for proper removal installation proce dures WATER PUMP 5 2L 5 9L ENGINES REMOVAL The water pump can be removed and installed without discharging the air c
49. flow tank Use a 50 50 mixture of ethylene glycol antifreeze containing Alugard 340 2 and low mineral content water Remove radiator cap only for testing or when refill ing system after service Removing cap unnecessarily can cause loss of coolant and allow air to enter sys tem which produces corrosion COOLANT LEVEL CHECK The cooling system is closed and designed to main tain coolant level to top of radiator WARNING DO NOT OPEN RADIATOR DRAINCOCK WITH ENGINE RUNNING OR WHILE ENGINE IS HOT AND COOLING SYSTEM IS UNDER PRESSURE Remove radiator cap The coolant level should be to top of radiator If not and if coolant level in cool ant recovery bottle is at ADD mark check for e An air leak in coolant reserve overflow tank or its hose e An air leak in radiator filler neck e Leak in pressure cap seal to radiator filler neck COOLING SYSTEM DRAINING AND FILLING WARNING DO NOT REMOVE CYLINDER BLOCK DRAIN PLUGS OR LOOSEN RADIATOR DRAIN COCK WITH SYSTEM HOT AND UNDER PRESSURE SERIOUS BURNS FROM COOLANT CAN OCCUR DO NOT WASTE reusable coolant If solution is dean drain coolant into a dean container for reuse DRAINING NOTE On the 4 7L engine the thermostat is an inlet side thermostat This means that the engine coolant will not drain when the radiator drain petcock is opened It will be necessary to remove the thermo stat housing and thermostat to allow the coolant traped in the engine block to drain 1 R
50. for ven tilation The water pump seals are lubricated by 7 6 COOLING SYSTEM DESCRIPTION AND OPERATION Continued 80bdbd2e Fig 7 Radiator Typical 1 RADIATOR 2 A C CONDENSER IF EQUIPPED 3 TRANSMISSION AUXILIARY OIL COOLER antifreeze in the coolant mixture Additional lubrica tion is not necessary 80bdbd2c Fig 8 Water Pump Location Typical 1 WATER PUMP BYPASS HOSE 2 FAN BLADE ASSEMBLY 3 VISCOUS FAN DRIVE 4 WATER PUMP AND PULLEY DN WATER PUMP BYPASS 4 7L DESCRIPTION The 4 7L engine uses an internal water coolant bypass system The design uses galleries in the tim ing chain cover to circulate coolant during engine warm up preventing the coolant from flowing through the radiator The thermostat uses a stub shaft located at the rear of the thermostat Fig 9 to control flow through the bypass gallery THERMOSTAT SHOWN IN THE CLOSED POSITION 80b897e4 Fig 9 Water Coolant Bypass Flow and Thermostat 4 7L Engine 1 FROM HEATER 2 FROM RADIATOR 3 TO WATER PUMP 4 ENGINE BYPASS 5 THERMOSTAT OPERATION A centrifugal water pump circulates coolant through the water jackets passages intake manifold radiator core cooling system hoses and heater core this coolant absorbs the heat generated when the engine is running The pump is driven by the engine crankshaft via a drive belt OPERATION When the thermostat is in the close
51. ge on 4 7L 5 2L or 5 9L engines 80be4d0c Fig 13 Automatic Belt Tensioner 5 2L 5 9L Engines 1 AUTOMATIC TENSIONER 2 COIL AND BRACKET 3 SCREW AND WASHER 80ba780b Fig 14 Automatic Belt Tensioner 4 7L Engine 1 AUTOMATIC TENSIONER ASSEMBLY OPERATION The automatic belt tensioner maintains belt ten sion by using internal spring pressure a pivoting arm and pulley to press against the drive belt BLOCK HEATER DESCRIPTION WARNING DO NOT OPERATE ENGINE UNLESS BLOCK HEATER CORD HAS BEEN DISCONNECTED FROM POWER SOURCE AND SECURED IN PLACE THE POWER CORD MUST BE SECURED IN ITS RETAINING CLIPS AND ROUTED AWAY FROM EXHAUST MANIFOLDS AND MOVING PARTS An optional engine block heater is available for all models The heater is equipped with a power cord The cord is attached to an engine compartment com ponent with tie straps The heater is mounted in a core hole of the engine cylinder block in place of a freeze plug with the heating element immersed in engine coolant 80b897e7 Fig 15 Block Heater 4 7L 1 ENGINE BLOCK HEATER OPERATION The heater warms the engine providing easier engine starting and faster warm up in low tempera tures The power cord must be conneced to a grounded 110 120 volt AC electrical outlet with a grounded three wire extension cord this provides the electricity to warm the heating element HOSE CLAMPS DESCRIPTION The cooling system utilizes bot
52. h with Adapter Pins 8346 can be used to hold the pulley still Fig 66 to prevent pulley from rotating 3 Do not attempt to remove fan viscous fan drive assembly from vehide at this time 4 Do not unbolt fan blade assembly Fig 68 from viscous fan drive at this time 5 Remove upper fan shroud attaching hardware Fig 69 6 Remove upper fan shroud and fan blade viscous fan drive from vehide 7 After removing fan blade viscous fan drive assembly do not place viscous fan drive in horizon tal position If stored horizontally silicone fluid in the viscous fan drive could drain into its bearing assembly and contaminate lubricant 8 Remove four bolts securing fan blade assembly to viscous fan drive Fig 68 INSTALLATION 1 Install fan blade assembly to viscous fan drive Tighten bolts Fig 68 to 23 N m 17 ft Ibs torque 2 Position fan blade viscous fan drive assembly and upper shroud into vehide 7 42 COOLING SYSTEM REMOVAL AND INSTALLATION Continued 80b6b293 Fig 66 Fan Blade and Viscous Fan Drive Removal 1 SPECIAL TOOL 6958 SPANNER WRENCH WITH ADAPTER PINS 8346 2 FAN 80bc4d15 Fig 67 Fan Blade Viscous Fan Drive 4 7L 5 2L 5 9L Engine 1 FAN AND VISCOUS DRIVE 2 WATER PUMP THREADED SHAFT 3 Install fan shroud retaining screws Fig 69 4 Install fan blade viscous fan drive assembly to water pump shaft Fig 67 5 Connect battery negative ca
53. h worm drive and spring type hose clamps If a spring type damp replacement is necessary replace with the original Mopar equipment spring type clamp CAUTION A number or letter is stamped into the tongue of constant tension clamps If replacement is necessary use only a original equipment clamp with matching number or letter Fig 16 OPERATION The worm type hose damp uses a specified torque value to maintain proper tension on a hose connec tion DN DESCRIPTION AND OPERATION Continued 80b76ee Fig 16 Spring Clamp Size Location 1 SPRING CLAMP SIZE LOCATION COOLING SYSTEM 7 9 80bc4d11 Fig 17 Fan Blade Viscous Fan Drive 4 7L 5 2L 5 9L Engines 1 VISCOUS FAN DRIVE 2 FAN BLADE 3 SCREW AND WASHER The spring type hose clamp applies constant ten sion on a hose connection To remove a spring type hose damp only use constant tension clamp pliers designed to compress the hose damp VISCOUS FAN DRIVE DESCRIPTION CAUTION Engines equipped with accessory drive belts have reverse rotating fans and viscous fan drives They are marked with the word REVERSE to designate their usage Installation of the wrong fan or viscous fan drive can result in engine overheat ing The thermal viscous fan drive is a silicone fluid filled coupling used to connect the fan blades to the water pump shaft The coupling allows the fan to be driven in a normal manner This is done at low engine speed
54. iagnosis charts for further belt diagnosis NOISE DIAGNOSIS Noises generated by the accessory drive belt are most noticeable at idle Before replacing a belt to resolve a noise condition inspect all of the accessory drive pulleys for alignment glazing or excessive end 2 play J9007 44 Fig 23 Belt Wear Patterns 1 NORMAL CRACKS BELT OK 2 NOT NORMAL CRACKS REPLACE BELT ACCESSORY DRIVE BELT DIAGNOSIS CHART CONDITION POSSIBLE CAUSES CORRECTION RIB CHUNKING One or 1 Foreign objects imbedded in pulley 1 Remove foreign objects from pulley more ribs has separated grooves grooves Replace belt from belt bod y 2 Installation damage 2 Replace belt RIB OR BELT WEAR 1 Pulley misaligned 1 Align pulley s 2 Abrasive environment 2 Clean pulley s Replace belt if necessary 3 Rusted pulley s 3 Clean rust from pulley s 4 Sharp or jagged pulley groove tips 4 Replace pulley Inspect belt 5 Belt rubber deteriorated 5 Replace belt BELT SLIPS 1 Belt slipping because of insufficient 1 Inspect Replace tensioner if tension necessary 2 Belt or pulley exposed to substance 2 Replace belt and clean pulleys that has reduced friction belt dressing oil ethylene glycol 3 Driven component bearing failure 3 Replace faulty component or bearing seizure 4 Belt glazed or hardened from heat 4 Replace belt and excessive slippage 7 20 COOLING SYSTEM DIAGNOSIS AND TESTING Continued CON
55. iator or A C condenser fins are dirty or clogged 11 Radiator core is corroded or plugged 12 Aftermarket A C installed without proper radiator 13 Fuel or ignition system problems 14 Dragging brakes 15 Bug screen or cardboard is being used reducing airflow 16 Thermostat partially or completely shut 17 Viscous fan drive not operating properly 18 Oylinder head gasket leaking 19 Heater core leaking 7 a Check condition of radiator cap and cap seals Refer to Radiator Cap in this Group Replace cap if necessary b Check condition of radiator filler neck If neck is bent or damaged replace radiator c Check condition of the hose from the radiator to the coolant tank It should fit tight at both ends without any kinks or tears Replace hose if necessary d Check coolant reserve overflow tank and tanks hoses for blockage Repair as necessary 8 Check coolant Refer to Coolant section in this Group for correct coolant water mixture ratio 9 Check for coolant flow at radiator filler neck with some coolant removed engine warm and thermostat open Coolant should be observed flowing through radiator If flow is not observed determine area of obstruction and repair as necessary 10 Remove insects and debris Refer to Radiator Cleaning in this Group 11 Have radiator re cored or replaced 12 Install proper radiator 13 Refer to Fuel and Ignition System Groups for diagnosis
56. ily 4 Coolant low in coolant reserve overflow tank and radiator 5 Pressure cap not installed tightly If cap is loose boiling point of coolant will be lowered Also refer to the following Step 6 6 Poor seals at the radiator cap 1 This may be a temporary condition and repair is not necessary Turn off the air conditioning and attempt to drive the vehicle without any of the previous conditions Observe the temperature gauge The gauge should return to the normal range If the gauge does not return to the normal range determine the cause for overheating and repair Refer to Possible Causes 2 20 2 Check gauge Refer to Group 8E Repair as necessary 3 Check warning lamp operation Refer to Group 8E Repair as necessary 4 Check for coolant leaks and repair as necessary Refer to Testing Cooling System for Leaks in this Group 5 Tighten cap 6 a Check condition of cap and cap seals Refer to Radiator Cap Replace cap if necessary b Check condition of radiator filler neck If neck is bent or damaged replace radiator 7 12 COOLING SYSTEM DIAGNOSIS AND TESTING Continued CONDITION POSSIBLE CAUSES DN CORRECTION 7 Coolant level low in radiator but not in coolant reserve overflow tank This means the radiator is not drawing coolant from the coolant reserve overflow tank as the engine cools 8 Incorrect coolant concentration 9 Coolant not flowing through system 10 Rad
57. itioning condenser 4 Thermal viscous fan drive has defective bearing 5 A certain amount of fan noise may be evident on models equipped with a thermal viscous fan drive Some of this noise is normal 1 Replace fan blade assembly Refer to Cooling System Fans in this Group 2 Locate point of fan blade contact and repair as necessary 3 Remove obstructions and or clean debris or insects from radiator or A C condenser 4 Replace fan drive Bearing is not serviceable Refer to Viscous Fan Drive in this group 5 Refer to Viscous Fan Drive in this group for an explanation of normal fan noise DN DIAGNOSIS AND TESTING Continued CONDITION POSSIBLE CAUSES COOLING SYSTEM 7 15 CORRECTION INADEQUATE HEATER PERFORMANCE THERMOSTAT FAILED IN OPEN POSITION 1 Has a Diagnostic trouble Code DTC been set 2 Coolant level low 3 Obstructions in heater hose fittings 4 Heater hose kinked 5 Water pump is not pumping water to through the heater core When the engine is fully warmed up both heater hoses should be hot to the touch If only one of the hoses is hot the water pump may not be operating correctly or the heater core may be plugged Accessory drive belt may be slipping causing poor water pump operation 1 Refer to Group 25 Emissions for correct procedures and replace thermostat if necessary 2 Refer to Cooling System Testing For Leaks in this group 3 Remove heater hoses at both
58. ling system and refill with water Run engine with radiator cap installed until upper radia tor hose is hot Stop engine and drain water from system If water is dirty fill system with water run engine and drain system Repeat until water drains clean REVERSE FLUSHING Reverse flushing of cooling system is the forcing of water through the cooling system This is done using air pressure in the opposite direction of normal cool ant flow It is usually only necessary with very dirty systems with evidence of partial plugging REVERSE FLUSHING RADIATOR Disconnect radiator hoses from radiator inlet and outlet Attach a section of radiator hose to radiator bottom outlet fitting and insert flushing gun Con nect a water supply hose and air supply hose to flushing gun CAUTION Internal radiator pressure must not exceed 138 kPa 20 psi as damage to radiator may result Allow radiator to fill with water When radiator is filled apply air in short blasts Allow radiator to refill between blasts Continue this reverse flushing until clean water flows out through rear of radiator cooling tube passages Have radiator cleaned more extensively by a radiator repair shop REVERSE FLUSHING ENGINE Drain cooling system Remove thermostat housing and thermostat Install thermostat housing Discon nect radiator upper hose from radiator and attach flushing gun to hose Disconnect radiator lower hose DN SERVICE PROCEDURES Continued from wat
59. mpressor Y Ss iet Fig 40 Generator A C Compressor Mounting Bracket 5 2L 5 9L Engine 1 IDLER PULLEY BUSHING 2 A C AND OR GENERATOR MOUNTING BRACKET 3 IDLER PULLEY 4 SCREW AND WASHER 80bc4do0d WARNING THE A C SYSTEM IS UNDER PRESSURE EVEN WITH ENGINE OFF REFER TO REFRIGER ANT WARNINGS IN GROUP 24 HEATING AND AIR CONDITIONING 1 Disconnect battery negative cable DN REMOVAL AND INSTALLATION Continued 2 Partially drain cooling system Refer to COOL ING SYSTEM DRAINING and FILLING in this Section Do not waste reusable coolant If solution is clean drain coolant into a clean container for reuse 3 Remove upper radiator hose clamp Fig 38 and hose at radiator 4 Unplug wiring harness from A C compressor 5 Remove air cleaner assembly 6 Remove accessory drive belt as follows The drive belt is equipped with a spring loaded automatic tensioner Fig 41 Relax tension from belt by rotat ing tensioner clockwise as viewed from front Fig 41 When all belt tension has been relaxed remove accessory drive belt J9219 15 Fig 41 Automatic Belt Tensioner Assembly 1 IDLER PULLEY 2 TENSIONER 3 FAN BLADE 7 The drive belt idler pulley must be removed to gain access to one of A C compressor generator bracket mounting bolts Remove idler pulley bolt and remove idler pulley Fig 40 8 Remove oil dipstick tube mounting bolt at sid
60. nt check for open shorted circuit C28 between the PDC and relay e With the ignition key in the run position check for battery voltage at circuit F18 relay terminal 86 If no battery voltage present check for open short in circuit F18 between the junction block and the relay e f no problems are detected install the DRB refer to the appropriate Powertrain Diagnostic Pro cedures manual for DRB scan tool operating instruc tions and start the engine Clip a 12V test light to the battery positive terminal and probe circuit C27 relay terminal 85 When the engine temperature reaches 110 C 230 F or A C is requested the test light should light If not check circuit C27 for open e f no problems are detected at this point replace the cooling fan relay DN 80a7aec4 Fig 20 Power Distribution Center PDC 1 POWER DISTRIBUTION CENTER PDC RADIATOR COOLANT FLOW CHECK Use the following procedure to determine if coolant is flowing through cooling system 1 Idle engine until operating temperature is reached If upper radiator hose is warm to the touch thermostat is opening and coolant is flowing to radi ator WARNING HOT PRESSURIZED COOLANT CAN CAUSE INJURY BY SCALDING USING A RAG TO COVER RADIATOR PRESSURE CAP OPEN RADIA TOR CAP SLOWLY TO FIRST STOP ALLOW ANY BUILT UP PRESSURE TO VENT TO THE RESERVE OVERFLOW TANK AFTER PRESSURE BUILD UP HAS BEEN RELEASED REMOVE CAP FROM FILLER NECK 2 Drain a sm
61. oles and inspect system again with pressure applied Drops Quickly Indicates that serious leakage is occurring Examine system for external leakage If leaks are not visible inspect for internal leakage Large radiator leak holes should be repaired by a reputable radiator repair shop INTERNAL LEAKAGE INSPECTION Remove engine oil pan drain plug and drain a small amount of engine oil If coolant is present in the pan it will drain first because it is heavier than oil An alternative method is to operate engine for a short period to churn the oil After this is done remove engine dipstick and inspect for water glob ules Also inspect transmission dipstick for water globules and transmission fluid cooler for leakage 7 18 COOLING SYSTEM DIAGNOSIS AND TESTING Continued WARNING WITH RADIATOR PRESSURE TESTER TOOL INSTALLED ON RADIATOR DO NOT ALLOW PRESSURE TO EXCEED 110 KPA 20 PSI PRES SURE WILL BUILD UP QUICKLY IF A COMBUSTION LEAK IS PRESENT TO RELEASE PRESSURE ROCK TESTER FROM SIDE TO SIDE WHEN REMOVING TESTER DO NOT TURN TESTER MORE THAN 1 2 TURN IF SYSTEM IS UNDER PRESSURE Operate engine without pressure cap on radiator until thermostat opens Attach a Pressure Tester to filler neck If pressure builds up quickly it indicates a combustion leak exists This is usually the result of a cylinder head gasket leak or crack in engine Repair as necessary If there is not an immediate pressure increase pump the Pressure Te
62. on of various corrosion inhibi tors causing damage to the various cooling system components Also once ethylene glycol and propy lene glycol based coolants are mixed in the vehicle conventional methods of determining freeze point will not be accurate Both the refractive index and spe cific gravity differ between ethylene glycol and propy lene glycol OPERATION ETHYLENE GLYCOL MIXTURES Coolant flows through the engine block absorbing the heat from the engine then flows to the radiator where the cooling fins in the radiator transfers the heat from the coolant to the atmosphere During cold weather the ethylene glycol coolant prevents water present in the cooling system from freezing within temperatures indicated by mixture ratio of coolant to water COOLANT SELECTION AND ADDITIVES The presence of aluminum components in the cool ing system requires strict corrosion protection Main tain coolant at specified level with a mixture of ethylene glycol based antifreeze and water Daimler COOLING SYSTEM 7 23 Chrysler Corporation recommends Mopar Antifreeze or equivalent If coolant becomes contaminated or looses color drain and flush cooling system and fill with correctly mixed solution CAUTION Do not use coolant additives that are claimed to improve engine cooling COOLANT ADDING ADDITIONAL Do not remove radiator cap to add coolant to system When adding coolant to maintain correct level do so at coolant reserve over
63. onditioning system if equipped 1 Disconnect battery negative cable 2 Drain cooling system Refer to Cooling Sys tem Draining and Filling in this group 3 Do not waste reusable coolant If solution is dean drain coolant into a clean container for reuse WARNING CONSTANT TENSION HOSE CLAMPS ARE USED ON MOST COOLING SYSTEM HOSES WHEN REMOVING OR INSTALLING USE ONLY TOOLS DESIGNED FOR SERVICING THIS TYPE OF COOLING SYSTEM 7 25 CLAMP SUCH AS SPECIAL CLAMP TOOL NUMBER 6094 Fig 38 SNAP ON CLAMP TOOL NUMBER HPC 20 MAY BE USED FOR LARGER CLAMPS ALWAYS WEAR SAFETY GLASSES WHEN SERVIC ING CONSTANT TENSION CLAMPS CAUTION A number or letter is stamped into the tongue of constant tension clamps Fig 39 If replacement is necessary use only an original equipment clamp with matching number or letter 4 Remove upper radiator hose clamp and hose at radiator 5 The thermal viscous fan drive is attached threaded to the water pump hub shaft Fig 29 Remove fan viscous fan drive assembly from water pump by turning mounting nut counterclockwise as viewed from front Threads on viscous fan drive are RIGHT HAND A Snap On 36 MM Fan Wrench number SP346 from Snap On Cummins Diesel Tool Set number 2017DSP and Special Tool 6958 Span ner Wrench with Adapter Pins 8346 can be used Place Special Tool 6958 Spanner Wrench onto the water pump pulley with Adapter Pins 8346 inserted into the holes on the pulley Fig 28
64. ostat spring side down into recessed machined groove on timing chain cover Fig 49 3 Position thermostat housing on timing chain cover 4 Install two housing to timing chain cover bolts Tighten bolts to 13 N m 115 in Ibs torque CAUTION Housing must be tightened evenly and thermostat must be centered into recessed groove in timimg chain cover If not it may result in a cracked housing damaged timing chain cover threads or coolant leaks DN REMOVAL AND INSTALLATION Continued COOLING SYSTEM 7 35 80b3b198 Fig 49 Thermostat and Thermostat Housing 4 7L 3 THERMOSTAT AND GASKET 4 TIMING CHAIN COVER 1 THERMOSTAT HOUSING 2 THERMOSTAT LOCATION 5 Install lower radiator hose on thermostat hous ing 6 Install splash shield 7 Lower vehicle 8 Fill cooling system Refer to Refilling Cooling System in this section 9 Connect negative battery cable to battery 10 Start and warm the engine Check for leaks RADIATOR REMOVAL WARNING DO NOT REMOVE CYLINDER BLOCK DRAIN PLUGS OR LOOSEN RADIATOR DRAIN COCK WITH SYSTEM HOT AND UNDER PRESSURE SERIOUS BURNS FROM COOLANT CAN OCCUR 1 Disconnect battery negative cable 2 Drain cooling system Refer to Draining and Filling Cooling System in this section WARNING CONSTANT TENSION HOSE CLAMPS ARE USED ON MOST COOLING SYSTEM HOSES WHEN REMOVING OR INSTALLING USE ONLY TOOLS DESIGNED FOR SERVICING THIS TYPE OF CLAMP SUC
65. rectly If not engine may overheat due to water pump rotating in wrong direction Refer to Fig 37 for correct belt COOLING SYSTEM 7 29 routing Or refer to the Belt Routing Label located in the engine compartment The correct belt with correct length must be used 80b76f69 Fig 37 Belt Routing 4 7L 1 GENERATOR PULLEY 2 ACCESSORY DRIVE BELT 3 POWER STEERING PUMP PULLEY 4 CRANKSHAFT PULLEY 5 IDLER PULLEY 6 TENSIONER 7 A C COMPRESSOR PULLEY 8 WATER PUMP PULLEY 6 Position upper fan shroud and fan blade vis cous fan drive assembly 7 Be sure the upper and lower portions of the fan shroud are firmly connected All air must flow through the radiator 8 Install two fan shroud to radiator screws Fig 34 9 Be sure of at least 25 mm 1 0 inches between tips of fan blades and fan shroud 10 Install fan blade viscous fan drive assembly to water pump shaft 11 Fill cooling system Refer to Refilling the Cool ing System in this group 12 Connect negative battery cable 13 Start and warm the engine Check for leaks 7 30 COOLING SYSTEM REMOVAL AND INSTALLATION Continued WATER PUMP BYPASS HOSE 5 2L 5 9L ENGINES REM OVAL WITHOUT AIR CONDITIONING 1 Partially drain cooling system Refer to COOL ING SYSTEM DRAINING and FILLING in this Section Do not waste reusable coolant If solution is dean drain coolant into a clean container for reuse WA
66. release range of 124 to 145 kPa 18 to 21 psi A rubber gasket seals the radiator filler neck This is done to maintain vacuum during coolant cool down and to prevent leakage when system is under pres sure OPERATION A vent valve in the center of the cap will remain shut as long as the cooling system is pressurized As the coolant cools it contracts and creates a vacuum in cooling system This causes the vacuum valve to open and coolant in reserve overflow tank to be drawn through connecting hose into radiator If the vacuum valve is stuck shut or overflow hose is kinked radiator hoses will collapse on cool down COOLING SYSTEM 7 5 CROSS SECTIONAL VIEW 80bc4e65 Fig 6 Radiator Pressure Cap Typical 1 FILLER NECK SEAL 2 VACUUM VENT VALVE 3 PRESSURE RATING 4 PRESSURE VALVE RADIATOR DESCRIPTION The radiator is a aluminum cross flow design with horizontal tubes through the radiator core and verti cal plastic side tanks OPERATION The radiator supplies sufficient heat transfer using the cooling fins interlaced between the horizontal tubes in the radaitor core to cool the engine and automatic transmission oil if equipped WATER PUMP DESCRIPTION The water pump is located on the engine front cover and has an integral pulley attached Fig 8 The water pump impeller is pressed onto the rear of a shaft that rotates in a bearing pressed into the water pump body The body has a small hole
67. s bends loose rivets or broken welds Replace fan if any damage is found SPECIFICATIONS COOLING SYSTEM CAPACITIES CAPACITY 5 2L 5 9L 13 5L 14 3 Qts 4 7L 12 3L 13 0 Qts Nominal refill capacities are shown A variation may be observed from vehicle due to manufacturing tolerances and refill procedures Capacities shown include vehicles with air conditioning and or heavy duty cooling systems 7 44 COOLING SYSTEM SPECIFICATIONS Continued COOLING SYSTEM DESCRIPTION Ft In QS a Automatic Belt Tensioner to Mounting Bracket Bolts 5 2L 5 9L els Automatic Belt Tensioner to Block Bolts E tela 41 30 Automatic Belt Tensioner 61 45 Pulley Bolt BoxHewe mat 2 17 Generator Compressor Mounting Bracket Bolts 54 40 40 30 Fan Shroud Mounting Bois 6 50 Fan Blade to Fan Drive Bolts Idler Pulley Bolt Radiator to Support Bolts Thermostat Housing Bolts Transmission Auxiliary Oil 10 Cooler Bolts Upper Radiator Closure Panel Bolts Water Pump Bolts o ao m e 3 SPECIAL TOOLS COOLING DN Cooling System Pressure Tester 7700A 3 8 Disconnect Tool 6935
68. s while limiting the top speed of the fan to a predetermined maximum level at higher engine speeds On all 4 7L an electrical cooling fan located in the fan shroud aids in low speed cooling It is designed to augment the viscous fan However it does not replace the viscous fan A thermostatic bimetallic spring coil is located on the front face of the viscous fan drive unit This spring coil reacts to the temperature of the radiator discharge air It engages the viscous fan drive for higher fan speed if the air temperature from the radiator rises above a certain point Until additional engine cooling is necessary the fan will remain at a reduced rpm regardless of engine speed J9307 31 Fig 18 Viscous Fan Drive 4 7L 5 2L 5 9L Engines Typical 1 VISCOUS FAN DRIVE 2 THERMOSTATIC SPRING 3 MOUNTING NUT TO WATER PUMP HUB OPERATION When sufficient heat is present the viscous fan drive will engage This is when the air flowing through the radiator core causes a reaction to the bimetallic coil It then increases fan speed to provide the necessary additional engine cooling Once the engine has cooled the radiator discharge temperature will drop The bimetallic coil again reacts and the fan speed is reduced to the previous disengaged speed 7 10 COOLING SYSTEM DIAGNOSIS AND TESTING ON BOARD DIAGNOSTICS OBD COOLING SYSTEM RELATED DIAGNOSTICS The powertrain control module PCM has been programmed to monitor
69. ster Do this until indicated pressure is within system range of 110 kPa 16 psi Fluctuation of gauge pointer indicates compression or combustion leakage into cooling system Because the vehicle is equipped with a catalytic converter do not remove spark plug cables or short out cylinders to isolate compression leak If the needle on dial of pressure tester does not fluctuate race engine a few times to check for an abnormal amount of coolant or steam This would be emitting from exhaust pipe Coolant or steam from exhaust pi pe may indicate a faulty cylinder head gas ket cracked engine cylinder block or cylinder head A convenient check for exhaust gas leakage into cooling system is provided by a commercially avail able Block Leak Check tool Follow manufacturers instructions when using this product COM BUSTION LEAKAGE TEST WITHOUT PRESSURE TESTER DO NOT WASTE reusable coolant If solution is dean drain coolant into a clean container for reuse WARNING DO NOT REMOVE CYLINDER BLOCK DRAIN PLUGS OR LOOSEN RADIATOR DRAIN COCK WITH SYSTEM HOT AND UNDER PRESSURE SERIOUS BURNS FROM COOLANT CAN OCCUR Drain sufficient coolant to allow thermostat removal Refer to Thermostat Replacement Discon nect water pump drive belt Add coolant to radiator to bring level to within 6 3 mm 1 4 in of top of thermostat housing CAUTION Avoid overheating Do not operate engine for an excessive period of time Open drain cock immediately
70. tem in this group 3 Remove power cord from block heater Fig 55 4 Loosen screw at center of block heater Remove heater assembly and o ring seal INSTALLATION 1 Thoroughly dean cylinder block core hole and block heater seat 2 all except 4 7L Engine Position o ring seal on heater then insert block heater assembly with ele ment loop pointing down Fig 55 3 4 7L Engine Only Insert block heater assem bly with element loop pointing upward 12 O dock Fig 56 4 With block heater fully seated tighten center screw to 2 N m 17 in Ibs torque 5 Fill cooling system with recommended coolant Refer to Filling Cooling System section in this group 6 Start and warm the engine Check for leaks ACCESSORY DRIVE BELT 5 2L 5 9L ENGINE REM OVAL Drive belts on 5 2L 5 9L engines are equipped with a spring loaded automatic belt tensioner Fig 57 This belt tensioner will be used on all belt configura COOLING SYSTEM 7 37 80c070d1 Fig 55 Block Heater Removal Installation 5 2L 5 9L 1 BLOCK HEATER POWER CORD 2 POWER CORD ROUTING CLIP 2 3 FREEZE PLUG 4 O RING SEAL 5 BLOCK HEATER 80b897e7 Fig 56 Engine Block Heater 4 7L 1 ENGINE BLOCK HEATER tions such as with or without power steering or air conditioning For more information refer to Auto matic Belt Tensioner 5 2L 5 9L Engine in this sec tion 7 38 COOLING SYSTEM REMOVAL AND INSTALLAT
71. the appropriate Powertrain Diag nostic Procedures manual for diagnostic information and operation of the DRB scan tool RADIATOR CAP TO FILLER NECK SEAL PRESSURE RELIEF CHECK The pressure cap upper gasket seal pressure relief can be tested by removing overflow hose from radiator filler neck nipple Attach hose of pressure tester tool 7700 or equivalent to nipple It will be necessary to disconnect hose from its adapter for filler neck Pump air into radiator The pressure cap upper gasket should relieve at 69 124 kPa 10 18 psi and hold pressure at a minimum of 55 kPa 8 psi WARNING THE WARNING WORDS DO NOT OPEN HOT ON RADIATOR PRESSURE CAP ARE A SAFETY PRECAUTION WHEN HOT PRESSURE BUILDS UP IN COOLING SYSTEM TO PREVENT SCALDING OR INJURY RADIATOR CAP SHOULD NOT BE REMOVED WHILE SYSTEM IS HOT AND OR UNDER PRESSURE Do not remove radiator cap at any time except for the following purposes 1 Check and adjust antifreeze freeze point 2 Refill system with new antifreeze 3 Conducting service procedures 4 Checking for vacuum leaks WARNING IF VEHICLE HAS BEEN RUN RECENTLY WAIT AT LEAST 15 MINUTES BEFORE REMOVING RADIATOR CAP WITH A RAG SQUEEZE RADIATOR UPPER HOSE TO CHECK IF SYSTEM IS UNDER PRESSURE PLACE A RAG OVER CAP AND WITH OUT PUSHING CAP DOWN ROTATE IT COUNTER CLOCKWISE TO FIRST STOP ALLOW FLUID TO ESCAPE THROUGH THE COOLANT RESERVE COOLING SYSTEM 7 21 OVERFLOW HOSE INTO RESERVE O
72. to prevent pul ley from rotating Do not attempt to remove fan vis cous fan drive assembly from vehicle at this time 80b6b293 Fig 28 Viscous Fan Drive Removal Installation 1 SPECIAL TOOL 6958 SPANNER WRENCH WITH ADAPTER PINS 8346 2 FAN 7 26 COOLING SYSTEM REMOVAL AND INSTALLATION Continued 80bdbd2c Fig 29 Fan Blade and Viscous Fan Drive 5 2L 5 9L Engines 1 WATER PUMP BYPASS HOSE 2 FAN BLADE ASSEMBLY 3 VISCOUS FAN DRIVE 4 WATER PUMP AND PULLEY 6 If water pump is being replaced do not unbolt fan blade assembly Fig 29 from thermal viscous fan drive 7 Remove fan shroud attaching hardware two bolts at bottom two dips at top 8 Remove fan shroud and fan blade viscous fan drive assembly from vehide as a complete unit 9 After removing fan blade viscous fan drive assembly do not place thermal viscous fan drive in horizontal position If stored horizontally silicone fluid in viscous fan drive could drain into its bearing assembly and contaminate lubricant 10 Remove accessory drive belt as follows The drive belt is equipped with a spring loaded automatic tensioner Fig 30 Relax tension from belt by rotat ing tensioner dockwise as viewed from front Fig 30 When all belt tension has been relaxed remove accessory drive belt 11 Remove lower radiator hose clamp and remove lower hose at water pump 12 Remove heater hose damp and heater hos
73. w System 1 RADIATOR 2 WASHER FLUID RESERVOIR 3 COOLANT OVERFLOW RESERVOIR 4 FAN SHROUD UPPER 5 SCREW 6 INTERLOCKING PINS 7 FAN SHROUD LOWER The same thermostat is used for winter and sum mer seasons An engine should not be operated with out a thermostat except for servicing or testing Operating without a thermostat causes longer engine warmup time unreliable warmup performance increased exhaust emissions and crankcase condensa tion that can result in sludge formation OPERATION The wax pellet is located in a sealed container at the spring end of the thermostat When heated the pellet expands overcoming closing spring tension and water pump pressure to force the valve to open THERMOSTAT 4 7L ENGINE DESCRIPTION CAUTION Do not operate an engine without a ther mostat except for servicing or testing A pellet type thermostat controls the operating temperature of the engine by controlling the amount of coolant flow to the radiator On all engines the thermostat is dosed below 195 F 90 C Above this temperature coolant is allowed to flow to the radia tor This provides quick engine warm up and overall temperature control On the 4 7L engine the thermo DN J9207 14 Fig 4 Thermostat Typical 1 THERMOSTAT HOUSING 2 GASKET 3 INTAKE MANIFOLD 4 THERMOSTAT 5 MACHINED GROOVE stat is designed to block the flow of the coolant bypass journal by 5096 inste
74. ype of cooler is the in radiator type or oil to coolant type This type oil cooler is not serviceable The second type used is a remote type auxiliary oil cooler or oil to air cooler The oil to air type cooler is located in front of the radiator and is serviceable COOLING SYSTEM 7 7 o FRONT OF VEHICLE 3 80b898b4 Fig 11 Oil Flow to Cooler Top View Typical 1 TRANSMISSION OIL COOLER 2 AUTOMATIC TRANSMISSION 3 RETURN LINE 4 PRESSURE LINE D j SA EL CN o LE Oy scl 5499 QS 23 80bdbd2e Fig 12 Auxiliary Transmission Oil Cooler Typical 1 RADIATOR 2 A C CONDENSER IF EQUIPPED 3 TRANSMISSION AUXILIARY OIL COOLER AUTOMATIC BELT TENSIONER DESCRIPTION Correct drive belt tension is required to ensure optimum performance of the belt driven engine acces sories If specified tension is not maintained belt slippage may cause engine overheating lack of power steering assist loss of air conditioning capac ity reduced generator output rate and greatly reduced belt life It is not necessary to adjust belt tension on the 4 7L 5 2L or 5 9L engines These engines are equipped with an automatic belt tensioner Fig 13 Fig 14 The tensioner maintains correct belt ten sion at all times Due to use of this belt tensioner do 7 8 COOLING SYSTEM ON DESCRIPTION AND OPERATION Continued not attempt to use a belt tension gau

COOLING SYSTEM

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