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INSTALLATION
(1) Align the mounting pins into the slots on the fan shroud and push the container into the fan shroud.
(2) Secure the coolant container to the fan shroud
with bolts. Tighten to 8.5 N-m (75 in. lbs).
NOTE: Ensure the locking feature on the mounting pins has engaged.
(3) Connect the supply and return hoses to the container and ensure that the hose clamps are posi- tioned properly.
(4) Refill the cooling system(Refer to 7 - COOLING
- STANDARD PROCEDURE).
RADIATOR FAN REMOVAL
If
the viscous fan drive is replaced CAUTION: because of mechanical damage, the cooling fan blades should also be inspected. Inspect for fatigue cracks, loose blades, or loose rivets that could have resulted from excessive vibration. Replace fan blade assembly if any of these conditions are found. Also inspect water pump bearing and shaft assembly for any related damage due to a viscous fan drive malfunction.
(1) Disconnect negative battery cable from battery. (2) Remove coolant reserve/overflow container from fan shroud and lay aside. Do Not disconnect the hoses or drain coolant from the container.
(3) The thermal viscous fan drive/fan blade assem- bly is attached (threaded) to the water pump hub shaft (Fig. 4). Remove the fan blade/viscous fan drive assembly from the water pump by turning the mounting nut counterclockwise as viewed from the front. Threads on the viscous fan drive are RIGHT- HAND. A 36 MM Fan Wrench should be used to pre- vent pulley from rotating (Fig. 3).
(4) Do Not attempt to remove the fan/viscous fan
drive assembly from the vehicle at this time.
(5) Do Not unbolt the fan blade assembly (Fig. 4)
from viscous fan drive at this time.
(6) Remove the fan shroud-to-radiator mounting
(7) Pull the lower shroud mounts out of the radia-
bolts.
tor tank clips.
(8) Remove the fan shroud and fan blade/viscous fan drive assembly as a complete unit from vehicle. (9) After removing the fan blade/viscous fan drive assembly, do not place the viscous fan drive in a horizontal position. If stored horizontally, silicone
Fig.2CoolantDegasContainer
1 - SCREWS 2 - COOLANT DEGAS CONTAINER 3 - FAN SHROUD 4 - RADIATOR
The air space also acts as sort of a spring that pro- vides constant system pressurization in conjunction with the radiator cap on top of the container. By returning coolant to the pump side of the inlet ther- mostat, the degas container also supplies greater pressure to the coolant pump, providing for enhanced coolant flow at high engine speeds.
The degas container also provides a convenient and safe method for checking the coolant level with out removing the radiator pressure cap. The degas con- tainer does not require a separate overflow container since it was designed with enough volume to provide a coolant reserve and also protect for any after-boil conditions.
REMOVAL
(1) Drain enough coolant from the system so that the degas container is empty. Refer to Draining Cool- ing System 3.7L/4.7L Engines in this group
(2) Loosen the clamps securing the supply and return hoses to the container and remove the hoses. (3) Remove the coolant container to fan shroud
mounting bolts.
(4) Tilt the container back towards the engine to disengage the mounting pin locking features and lift the container away from the fan shroud.
ENGINE
7 - 40
RADIATOR FAN (Continued)Fig.3UsingSpecialTool6958SpannerWrench
1 - SPECIAL TOOL 6958 SPANNER WRENCH WITH ADAPTER PINS 8346
2 - FANFig.4FanBlade/ViscousFanDrive-GasEngines-
Typical
1 - WATER PUMP BYPASS HOSE 2 - FAN BLADE ASSEMBLY 3 - VISCOUS FAN DRIVE 4 - WATER PUMP AND PULLEY
fluid in the viscous fan drive could drain into its bearing assembly and contaminate lubricant.
CAUTION: Do not remove water pump pulley-to-wa- ter pump bolts. This pulley is under spring tension.
(10) Remove four bolts securing fan blade assem-
bly to viscous fan drive (Fig. 4).
DR
CAUTION: Some engines equipped with serpentine 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 overheating.
CLEANING
Clean the fan blades using a mild soap and water.
Do not use an abrasive to clean the blades.
INSPECTION
WARNING: DO NOT ATTEMPT TO BEND OR STRAIGHTEN FAN BLADES IF FAN IS NOT WITHIN SPECIFICATIONS.
If
CAUTION: 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 (six 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 cracks, bends, or bro-
ken welds. Replace fan if any damage is found.
INSTALLATION
(1) Install fan blade assembly to the viscous fan drive. Tighten the bolts (Fig. 4) to 24 N·m (18 ft. lbs.) torque.
(2) Position the fan shroud and the fan blade/vis- cous fan drive assembly to the vehicle as a complete unit.
(3) Install the fan shroud. (4) Install the fan blade/viscous fan drive assembly
to the water pump shaft (Fig. 4).
(5)
Install the coolant reserve/overflow container
to the fan shroud.
(6) Connect the negative battery cable.
NOTE: Viscous Fan Drive Fluid Pump Out Requirement: After installing a new viscous fan drive, bring the engine speed up to approximately 2000 rpm and hold for approximately two minutes. This will ensure proper fluid distribution within the drive.
DR
ENGINE
7 - 41
RADIATOR FAN - 5.9L DIESEL REMOVAL
CAUTION: If the electronically controlled viscous fan drive is replaced because of mechanical dam- age, the cooling fan blades should also be inspected. Inspect for fatigue cracks, or loose rivets that could have resulted from excessive vibration. Replace fan blade assembly if any of these condi- tions are found. Also inspect wiring harness and connectors for damage.
(1) Disconnect the battery negative cables. (2) Remove the fan shroud lower half. by unsnap-
ping the fastening tabs.
CAUTION: Do not remove the fan pulley bolts. This pulley is under spring tension.
(3) Disconnect electrical connector. (4) The electronically controlled viscous fan drive/ fan blade assembly is attached (threaded) to the fan hub shaft (Fig. 5). Remove the fan blade/fan drive assembly from fan pulley by turning the mounting nut counterclockwise (as viewed from front). Threads on the viscous fan drive are RIGHT-HAND. A Snap-On 36 MM Fan Wrench (number SP346 from Snap-On Cummins Diesel Tool Set number 2017DSP) can be used. Place a bar or screwdriver between the fan pulley bolts to prevent pulley from rotating.
(5) Remove the fan shroud and the fan blade/vis- cous drive as an assembly from vehicle from under the vehicle.
(6) Remove fan blade-to-viscous fan drive mount-
(7) Inspect the fan for cracks, loose or bent fan
ing bolts.
blades.
CAUTION: Some engines equipped with serpentine drive belts have reverse rotating fans and viscous fan drives. Installation of the wrong fan or viscous fan drive can result in engine overheating.
CLEANING
Clean the fan blades using a mild soap and water.
Do not use an abrasive to clean the blades.
INSPECTION
WARNING: DO NOT ATTEMPT TO BEND OR STRAIGHTEN FAN BLADES IF FAN IS NOT WITHIN SPECIFICATIONS.
Fig.5FanBlade/ViscousFanDrive
1 - ELECTRICAL CONNECTOR 2 - VISCOUS FAN DRIVE 3 - FAN BLADE 4 - BOLT 5 - FAN DRIVE
If
CAUTION: 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 (six 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 cracks, bends, or bro-
ken welds. Replace fan if any damage is found.
INSTALLATION
(1) Install fan blade assembly to electrically con- trolled viscous fan drive. Tighten mounting bolts to 23 N·m (17 ft. lbs.) torque.
(2) Position the fan blade/viscous fan drive to the
vehicle as an assembly.
(3) Install viscous fan drive assembly on fan hub shaft (Fig. 5). Tighten mounting nut to 33 N·m (24 ft. lbs.) torque.
(4) Connect electrical connector.
ENGINE
7 - 42
RADIATOR FAN - 5.9L DIESEL (Continued)DR
(5) Install the lower fan shroud into position and
verify the locking tabs have seated.
(6) Connect the battery negative cables.
NOTE: Viscous Fan Drive Fluid Pump Out Requirement: After installing a new viscous fan drive, bring the engine speed up to approximately 2000 rpm and hold for approximately two minutes. This will ensure proper fluid distribution within the drive.
ENGINE 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 with 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 warms the engine providing easier engine starting and faster warm-up in low temperatures. 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. The 5.9L gas powered engine has the block heater located on the right side of engine next to the oil filter (Fig. 6). The 3.7L/4.7L gas powered engines have the block heater located to the rear on the right side of the engine (Fig. 7). OPERATION
The heater warms the engine coolant providing easier engine starting and faster warm-up in low temperatures. Connecting the power cord to a grounded 110-120 volt AC electrical outlet with a grounded three wire extension cord provides the elec- tricity needed to heat the element. DIAGNOSIS AND TESTING — ENGINE BLOCK HEATER
If the unit does not operate, possible causes can be either the power cord or the heater element. Test the power cord for continuity with a 110-volt voltmeter or 110-volt test light. Test heater element continuity with an ohmmeter or a 12-volt test light.
CAUTION: To prevent damage, the power cord must be secured in it’s retainer clips and away from any components that may cause abrasion or damage, such as linkages, exhaust components, etc.
Fig.6EngineBlockHeater-5.9L
1 - FREEZE PLUG HOLE 2 - BLOCK HEATER 3 - SCREW 4 - POWER CORD (120V AC) 5 - HEATING COIL 6 - OIL FILTER
Fig.7EngineBlockHeater-3.7L/4.7L
1 - ENGINE BLOCK HEATER
DR ENGINE BLOCK HEATER (Continued) REMOVAL
(1) Disconnect the battery negative cable. (2) Drain the coolant (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(3) Remove the power cord from the heater by
unplugging (Fig. 8).
(4) Loosen (but do not completely remove) the
screw at center of block heater (Fig. 8).
(5) Remove the block heater by carefully prying from side-to-side. Note the direction of the heating element coil (up or down). The element coil must be installed correctly to prevent damage.
Fig.8EngineBlockHeater
1 - FREEZE PLUG HOLE 2 - BLOCK HEATER 3 - SCREW 4 - POWER CORD (120V AC) 5 - HEATING COIL 6 - OIL FILTER
INSTALLATION
(1) Clean and inspect the block heater hole. (2) Install the new O-ring seal(s) to heater. (3) Insert the block heater into cylinder block and
position the element properly.
(4) With the heater fully seated, tighten center
screw to 2 N·m (17 in. lbs.).
(5) Fill the cooling system with the recommended coolant. (Refer to 7 - COOLING - STANDARD PRO- CEDURE).
(6) Start and warm the engine. (7) Check the block heater for leaks.
ENGINE
7 - 43
ENGINE BLOCK HEATER - 5.9L DIESEL 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 on all models. The heater is equipped with a power cord. The heater is mounted in a threaded hole of the engine cylinder block with the heating element immersed in engine coolant. The cord is attached to an engine compartment component with tie-straps.
The 5.9L diesel engine has the block heater located on the right side of the engine below the exhaust manifold next to the oil cooler (Fig. 9).
Fig.9EngineBlockHeater–5.9LDieselEngine
1 - BLOCK HEATER
OPERATION
The heater warms the engine coolant providing easier engine starting and faster warm-up in low temperatures. Connecting the power cord to a grounded 110-120 volt AC electrical outlet with a grounded three wire extension cord provides the elec- tricity needed to heat the element.
REMOVAL
(1) Disconnect the battery negative cables. (2) Drain coolant from radiator and cylinder block (Refer to 7 - COOLING - STANDARD PROCE- DURE).
(3) Unscrew the power cord retaining cap and dis-
connect cord from heater element.
ENGINE
7 - 44
ENGINE BLOCK HEATER - 5.9L DIESEL (Continued)DR
(4) Using a suitable size socket, loosen and remove
the block heater element (Fig. 10).
Fig.10BlockHeater-DieselEngine
1 - BLOCK HEATER
INSTALLATION
(1) Clean and inspect the threads in the cylinder
block.
ing cap.
(2) Coat heater element
threads with Mopart
Thread Sealer with Teflon.
(3) Screw block heater into cylinder block and
tighten to 43 N·m (32 ft. lbs.).
(4) Connect block heater cord and tighten retain-
(5) Fill cooling system with recommended coolant (Refer to 7 - COOLING - STANDARD PROCE- DURE).
(6) Start and warm the engine. (7) Check block heater for leaks.
ENGINE COOLANT TEMPERATURE SENSOR DESCRIPTION
The Engine Coolant Temperature (ECT) sensor is used to sense engine coolant temperature. The sensor protrudes into an engine water jacket.
The ECT sensor is a two-wire Negative Thermal Coefficient (NTC) sensor. Meaning, as engine coolant temperature increases, resistance (voltage) in the sensor decreases. As temperature decreases, resis- tance (voltage) in the sensor increases.
OPERATION
At key-on, the Powertrain Control Module (PCM) sends out a regulated 5 volt signal to the ECT sensor. The PCM then monitors the signal as it passes through the ECT sensor to the sensor ground (sensor return).
When the engine is cold, the PCM will operate in Open Loop cycle. It will demand slightly richer air- fuel mixtures and higher idle speeds. This is done until normal operating temperatures are reached.
following calculations:
through CCD or PCI (J1850) communications
The PCM uses inputs from the ECT sensor for the † for engine coolant temperature gauge operation † Injector pulse-width † Spark-advance curves † ASD relay shut-down times † Idle Air Control (IAC) motor key-on steps † Pulse-width prime-shot during cranking † O2 sensor closed loop times † Purge solenoid on/off times † EGR solenoid on/off times (if equipped) † Leak Detection Pump operation (if equipped) † Radiator fan relay on/off times (if equipped) † Target idle speed
REMOVAL
3.7L V-6
The Engine Coolant Temperature (ECT) sensor on the 3.7L engine is installed into a water jacket at front of intake manifold near rear of generator (Fig. 11).
WARNING: HOT, PRESSURIZED COOLANT CAN CAUSE INJURY BY SCALDING. COOLING SYSTEM MUST BE PARTIALLY DRAINED BEFORE REMOV- ING THE COOLANT TEMPERATURE SENSOR.
(1) Partially drain the cooling system. (2) Disconnect the electrical connector from the
sensor.
(3) Remove the sensor from the intake manifold.
4.7L V-8
WARNING: HOT, PRESSURIZED COOLANT CAN CAUSE INJURY BY SCALDING. COOLING SYSTEM MUST BE PARTIALLY DRAINED BEFORE REMOV- ING THE ENGINE COOLANT TEMPERATURE (ECT) SENSOR.
The Engine Coolant Temperature (ECT) sensor on the 4.7L V-8 engine is located near the front of the intake manifold (Fig. 12).
(1) Partially drain the cooling system. Refer to 7,
COOLING.
ECT sensor.
(2) Disconnect the electrical connector from the
(3) Remove the sensor from the intake manifold.
DR ENGINE COOLANT TEMPERATURE SENSOR (Continued)
ENGINE
7 - 45
compressor (Fig. 13). It is installed into a water jacket at the front of the cylinder block (Fig. 14).
WARNING: HOT, PRESSURIZED COOLANT CAN CAUSE INJURY BY SCALDING. COOLING SYSTEM MUST BE PARTIALLY DRAINED BEFORE REMOV- ING THE COOLANT TEMPERATURE SENSOR.
(1) Partially drain the cooling system. (2) Remove fan belt. Refer to Accessory Drive in
Cooling section.
(3) Carefully unbolt air conditioning compressor from front of engine. Do not disconnect any A/C hoses from compressor. Temporarily support compressor to gain access to ECT sensor. Refer to Heating and Air Conditioning section for information.
(4) Disconnect electrical
connector
from sensor
(Fig. 14).
(5) Remove sensor from cylinder block.
Fig.11MAPSENSOR/ECTSENSOR-3.7LV-6
1 - MOUNTING SCREWS 2 - MAP SENSOR 3 - ECT SENSOR 4 - FRONT OF INTAKE MANIFOLD
Fig.12ECTSENSOR-4.7LV-8
1 - ECT SENSOR 2 - MOUNTING BOLTS (2) 3 - MAP SENSOR 4 - INTAKE MANIFOLD
5.7L V-8
Fig.13ECTLOCATION-5.7LV-8
1 - TOP OF AIR CONDITIONING COMPRESSOR 2 - ECT SENSOR LOCATION
5.9L Diesel
The Engine Coolant Temperature (ECT) sensor on the 5.9L diesel engine is located near the thermostat housing (Fig. 15).
WARNING: HOT, PRESSURIZED COOLANT CAN CAUSE INJURY BY SCALDING. COOLING SYSTEM MUST BE PARTIALLY DRAINED BEFORE REMOV- ING THE COOLANT TEMPERATURE SENSOR.
The Engine Coolant Temperature (ECT) sensor on the 5.7L engine is located under the air conditioning
(1) Partially drain the cooling system.
ENGINE
7 - 46
ENGINE COOLANT TEMPERATURE SENSOR (Continued) 5.9L V-8 GasDR
WARNING: HOT, PRESSURIZED COOLANT CAN CAUSE INJURY BY SCALDING. COOLING SYSTEM MUST BE PARTIALLY DRAINED BEFORE REMOV- ING THE COOLANT TEMPERATURE SENSOR. REFER TO GROUP 7, COOLING.
(1) Partially drain the cooling system. Refer to 7,
(2) Disconnect the electrical connector from the
COOLING.
sensor (Fig. 16).
(3) Engines with air
conditioning: When removing the connector from the sensor, do not pull directly on the wiring harness. The connector is snapped onto the sensor. It is not equipped with a lock type tab.
(4) Remove the sensor from the intake manifold.
Fig.14ECTREMOVE/INSTALL5.7LV-8
1 - FRONT OF INTAKE MANIFOLD 2 - ELECTRICAL CONNECTOR 3 - ECT SENSOR
(2) Disconnect the electrical connector from the
sensor.
(3) Remove the sensor from the cylinder head.
Fig.15ECTLOCATION-5.9LDIESEL
1 - THERMOSTAT HOUSING 2 - ELECTRICAL CONNECTOR 3 - ECT SENSOR
Fig.16ECTSENSOR-5.9LV-8
1 - GENERATOR 2 - A/C COMPRESSOR 3 - ENGINE COOLANT TEMPERATURE SENSOR 4 - ELEC. CONN.
8.0L V-10
The Engine Coolant Temperature (ECT) sensor on the 8.0L V-10 engine is threaded into the thermostat housing (Fig. 17).
WARNING: HOT, PRESSURIZED COOLANT CAN CAUSE INJURY BY SCALDING. COOLING SYSTEM MUST BE PARTIALLY DRAINED BEFORE REMOV- ING THE COOLANT TEMPERATURE SENSOR.
(1) Partially drain the cooling system. (2) Disconnect the electrical connector from the
sensor.
(3) Remove the sensor from the cylinder head.
DR ENGINE COOLANT TEMPERATURE SENSOR (Continued)
ENGINE
7 - 47
(5) Replace any lost engine coolant. Refer to 7,
COOLING.
5.9L Diesel
(1) Apply thread sealant to sensor threads. (2) Install sensor to engine. (3) Tighten sensor to 18 N·m (13 ft. lbs.) torque. (4) Connect electrical connector to sensor. (5) Replace any lost engine coolant. Refer to 7,
COOLING.
5.9L V-8 Gas
(1) Apply thread sealant to sensor threads. (2) Install sensor to engine. (3) Tighten sensor to 6–8 N·m (55–75 in.
lbs.)
torque.
(4) Connect electrical connector to sensor. The sen- sor connector is symmetrical (not indexed). It can be connected to sensor in either direction.
(5) Refill cooling system. Refer to 7, COOLING.
Fig.17ECTSENSOR-8.0LV-10
1 - ENGINE COOLANT TEMP. SENSOR (FOR PCM) 2 - HEATER SUPPLY FITTING 3 - BOLTS (6) 4 - HOUSING WITH INTEGRAL SEAL 5 - THERMOSTAT 6 - RUBBER LIP SEAL 7 - TEMP. GAUGE SENDING UNIT
INSTALLATION
3.7L V-6
(1) Apply thread sealant to sensor threads. (2) Install sensor to engine. (3) Tighten sensor to 11 N·m (8 ft. lbs.) torque. (4) Connect electrical connector to sensor. (5) Replace any lost engine coolant. Refer to 7,
COOLING.
4.7L V-8
(1) Apply thread sealant to sensor threads. (2) Install sensor to engine. (3) Tighten sensor to 11 N·m (8 ft. lbs.) torque. (4) Connect electrical connector to sensor. (5) Replace any lost engine coolant. Refer to 7,
COOLING.
5.7L V-8
(1) Apply thread sealant to sensor threads. (2) Install sensor to engine. (3) Tighten sensor to 11 N·m (8 ft. lbs.) torque. (4) Connect electrical connector to sensor.
8.0L V-10
(1) Apply thread sealant to sensor threads. (2) Install sensor to engine. (3) Tighten sensor to 11 N·m (8 ft. lbs.) torque. (4) Connect electrical connector to sensor. (5) Replace any lost engine coolant. Refer to 7,
COOLING.
ENGINE COOLANT THERMOSTAT- 5.7L/5.9L DESCRIPTION
CAUTION: Do not operate an engine without a ther- mostat, except for servicing or testing.
The thermostat on the 5.7L and 5.9L gas powered engine is located beneath the thermostat housing at the front of the intake manifold (Fig. 18).
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.
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.
ENGINE
7 - 48
ENGINE COOLANT THERMOSTAT- 5.7L/5.9L (Continued)DR
REMOVAL
WARNING: DO NOT LOOSEN THE RADIATOR DRAINCOCK WITH THE COOLING SYSTEM HOT AND PRESSURIZED. SERIOUS BURNS FROM THE COOLANT CAN OCCUR.
Do not waste reusable coolant. If the solution is clean, drain the coolant into a clean container for reuse.
If the thermostat is being replaced, be sure that the replacement is the specified thermostat for the vehicle model and engine type.
Factory installed thermostat housings on 5.9L engine is installed on a gasket with an anti-stick coating. This will aid in gasket removal and clean-up.
(1) Disconnect the negative battery cable. (2) Drain the cooling system until the coolant level is below the thermostat (Refer to 7 - COOLING - STANDARD PROCEDURE).
(3) Air Conditioned vehicles: Remove the support bracket (generator mounting bracket-to-intake mani- fold) located near the rear of the generator (Fig. 19).
Fig.19GeneratorSupportBracket–5.9LEngine 1 - IDLER PULLEY BUSHING 2 - A/C AND/OR GENERATOR MOUNTING BRACKET 3 - IDLER PULLEY 4 - SCREW AND WASHER
NOTE: On air conditioning equipped vehicles, the generator must be partially removed.
(4) Remove the accessory drive belt (Refer to 7 - COOLING/ACCESSORY DRIVE/DRIVE BELTS - REMOVAL) (Fig. 20).
(5) Remove the generator mounting bolts. Do not remove any of If equipped with 4WD, unplug the 4WD indicator lamp wiring harness (located near rear of generator).
the wiring at
the generator.
(6) Remove the generator. Position the generator
to gain access for the thermostat gasket removal.
Fig.18Thermostat-5.7L/5.9LGasPowered
Engines
1 - THERMOSTAT HOUSING 2 - GASKET 3 - INTAKE MANIFOLD 4 - THERMOSTAT 5 - MACHINED GROOVE
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.
DIAGNOSIS AND TESTING—THERMOSTAT
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.
The DTC can also be accessed through the DRBIIIt scan tool. Refer to the appropriate Power- train Diagnostic Procedures information for diagnos- tic information and operation of the DRBIIIt scan tool.
DR ENGINE COOLANT THERMOSTAT- 5.7L/5.9L (Continued)
ENGINE
7 - 49
Fig.20AutomaticBeltTensioner–5.9LEngines
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. ALWAYS WEAR SAFETY GLASSES WHEN SERVICING CONSTANT TENSION CLAMPS.
CAUTION: A number or letter is stamped into the tongue of the constant tension clamps (Fig. 21). If is necessary, use only an original replacement equipment clamp with a matching number, letter and width.
(7) Remove the radiator upper hose clamp and
upper hose at the thermostat housing.
(8) Position the wiring harness (behind thermostat
housing) to gain access to the thermostat housing.
(9) Remove
thermostat housing mounting bolts, thermostat housing, gasket and thermostat (Fig. 22). Discard old gasket.
the
INSTALLATION
(1) Clean the mating areas of the intake manifold
and thermostat housing.
(2) Install the thermostat (spring side down) into the recessed machined groove on the intake manifold (Fig. 22).
(3) Install the gasket on the intake manifold and
over the thermostat (Fig. 22).
Fig.21SPRINGCLAMPSIZELOCATION
1 - SPRING CLAMP SIZE LOCATION
Fig.22Thermostat–5.9LEngines
1 - THERMOSTAT HOUSING 2 - GASKET 3 - INTAKE MANIFOLD 4 - THERMOSTAT 5 - MACHINED GROOVE
(4) Position the thermostat housing to the intake manifold. Note: The word FRONT stamped on hous- ing (Fig. 23). For adequate clearance, this must be placed towards the front of the vehicle. The housing is slightly angled forward after the installation to the intake manifold.
(5) Install
the housing-to-intake manifold bolts.
Tighten the bolts to 23 N·m (200 in. lbs.).
ENGINE
7 - 50
ENGINE COOLANT THERMOSTAT- 5.7L/5.9L (Continued)DR
Fig.23ThermostatPosition—5.9LEngines
(6) Install the radiator upper hose to the thermo-
stat housing.
CAUTION: When installing the serpentine accessory drive belt, the belt must be routed correctly. If not, the engine may overheat due to the water pump rotating in wrong direction. Refer to (Fig. 24) for the correct 5.9L engine belt routing. The correct belt with correct length must be used.
(7) Air Conditioned vehicles; Install the generator.
Tighten the bolts to 41 N·m (30 ft. lbs.).
(8) Install the support bracket (generator mount- ing bracket-to-intake manifold). (Fig. 19). Tighten the bolts to 54 N·m (40 ft. lbs.).
(9) Install the accessory drive belt (Fig. 20)(Refer - COOLING/ACCESSORY DRIVE/DRIVE
to BELTS - INSTALLATION).
(10) Fill the cooling system (Refer to 7 - COOLING
- STANDARD PROCEDURE).
(11) Connect battery negative cable. (12) Start and warm the engine. Check for leaks.
Fig.24BeltRouting–5.9LEngines
1 - IDLER PULLEY 2 - GENERATOR PULLEY 3 - A/C COMPRESSOR PULLEY 4 - IF W/OUT A/C 5 - POWER STEERING PUMP PULLEY 6 - WATER PUMP PULLEY 7 - CRANKSHAFT PULLEY 8 - AUTOMATIC TENSIONER
ENGINE COOLANT THERMOSTAT - 3.7L/4.7L DESCRIPTION
CAUTION: Do not operate the 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 closed 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 3.7L4.7L engine the thermostat is designed to block the flow of the cool- ant bypass journal by 50% instead of completely blocking the flow. This design controls coolant tem- perature more accurately (Fig. 25).
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 exhaust
performance,
increased
DR ENGINE COOLANT THERMOSTAT - 3.7L/4.7L (Continued)
ENGINE
7 - 51
emissions and crankcase condensation. This conden- sation can result in sludge formation.
the Diagnosis section of this group for other probable causes.
The DTC can also be accessed through the DRBIIIt scan tool. Refer to the appropriate Power- train Diagnostic Procedures information for diagnos- tic information and operation of the DRBIIIt scan tool.
REMOVAL
WARNING: DO NOT LOOSEN THE RADIATOR DRAINCOCK WITH THE COOLING SYSTEM HOT AND PRESSURIZED. SERIOUS BURNS FROM THE COOLANT CAN OCCUR.
Do not waste reusable coolant. If the solution is clean, drain the coolant into a clean container for reuse.
If the thermostat is being replaced, be sure that the replacement is the specified thermostat for the vehicle model and engine type.
(1) Disconnect the negative battery cable. (2) Drain the cooling system (Refer to 7 - COOL-
ING - STANDARD PROCEDURE).
(3) Raise and support the vehicle. (4) Remove the splash shield. (5) Remove the lower radiator hose clamp and the
lower radiator hose at the thermostat housing.
(6) Remove
the
thermostat housing mounting
bolts, thermostat housing and thermostat (Fig. 26).
INSTALLATION
(1) Clean the mating areas of the timing chain
cover and the thermostat housing.
(2) Install the thermostat (spring side down) into the recessed machined groove on the timing chain cover (Fig. 26).
(3) Position the thermostat housing on the timing
chain cover.
(4) Install the housing-to-timing chain cover bolts.
Tighten the bolts to 13 N·m (112 in. lbs.).
CAUTION: The housing must be tightened evenly and the thermostat must be centered into the recessed groove in the timimg chain cover. If not, it may result in a cracked housing, damaged timing chain cover threads or coolant leaks.
(5) Install the lower radiator hose on the thermo-
stat housing.
(6) Install the splash shield. (7) Lower the vehicle. (8) Fill the cooling system (Refer to 7 - COOLING
- STANDARD PROCEDURE).
(9) Connect negative battery cable. (10) Start and warm the engine. Check for leaks.
Fig.25ThermostatCrossSectionView3.7L/4.7L
1 - FROM HEATER AND DEGAS CONTAINER 2 - FROM RADIATOR 3 - TO WATER PUMP 4 - ENGINE BYPASS 5 - THERMOSTAT
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.
DIAGNOSIS AND TESTING—THERMOSTAT
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
ENGINE
7 - 52
ENGINE COOLANT THERMOSTAT - 3.7L/4.7L (Continued)DR
1 - THERMOSTAT HOUSING 2 - THERMOSTAT LOCATION
Fig.26ThermostatandThermostatHousing3.7L/4.7L 3 - THERMOSTAT AND GASKET 4 - TIMING CHAIN COVER
ENGINE COOLANT THERMOSTAT - 5.9L DIESEL DESCRIPTION
CAUTION: Do not operate an engine without a ther- mostat, except for servicing or testing. An engine with the thermostat removed will operate in the radiator bypass mode, causing an overheat condi- tion.
The thermostat of the 5.9L diesel engine is located in the front of the cylinder head, underneath the thermostat housing (Fig. 27).
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 will cause overheat- ing.
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.
DIAGNOSIS AND TESTING—THERMOSTAT
The cooling system used with the diesel engine provides the extra coolant capacity and extra cooling
Fig.27Thermostat–5.9LDiesel-Typical
1 - THERMOSTAT HOUSING 2 - CYLINDER HEAD 3 - THERMOSTAT
protection needed for higher GVWR (Gross Vehicle Weight Rating) and GCWR (Gross Combined Weight Rating) vehicles.
DR ENGINE COOLANT THERMOSTAT - 5.9L DIESEL (Continued)
ENGINE
7 - 53
This system capacity will not effect warm up or cold weather operating characteristics if the thermo- stat is operating properly. This is because coolant will be held in the engine until it reaches the ther- mostat “set” temperature.
Diesel engines, due to their inherent efficiency are slower to warm up than gasoline powered engines, and will operate at lower temperatures when the vehicle is unloaded. Because of this, lower tempera- ture gauge readings for diesel versus gasoline engines may, at times be normal.
Typically, complaints of low engine coolant temper- ature are observed as low heater output when com- bined with cool or cold outside temperatures.
To help promote faster engine warm-up, the elec- tric engine block heater must be used with cool or cold outside temperatures. This will help keep the engine coolant warm when the vehicle is parked. Use the block heater if the outside temperature is below 4°C (40°F). Do not use the block heater if the outside temperature is above 4°C (40°F).
A “Cold Weather Cover” is available from the parts department through the Mopar Accessories product line. This accessory cover is designed to block airflow entering the radiator and engine compartment to promote faster engine warm-up. It attaches to the front of the vehicle at the grill opening. The cover is to be used with cool or cold temperatures only. If used with high outside temperatures, serious engine damage could result. Refer to the litera- ture supplied with the cover for additional informa- tion.
(1) To determine if the thermostat is defective, it must be removed from the vehicle (Refer to 7 - COOLING/ENGINE/ENGINE COOLANT THERMO- STAT - REMOVAL).
(2) After the thermostat has been removed, exam- ine the thermostat and inside of thermostat housing for contaminants. If contaminants are found, the thermostat may already be in a “stuck open” position. Flush the cooling system before replacing thermostat (Refer to 7 - COOLING - STANDARD PROCE- DURE).
(3) Place the thermostat into a container filled
the valve is still moving when the water temperature reaches 97°C (207°F), it is opening too late. Replace thermostat. If the valve refuses to move at any time, replace thermostat.
REMOVAL
WARNING: DO NOT LOOSEN THE RADIATOR DRAINCOCK WITH THE SYSTEM HOT AND PRES- SURIZED. SERIOUS BURNS FROM THE COOLANT CAN OCCUR.
Do not waste reusable coolant. If the solution is clean, drain the coolant into a clean container for reuse.
(1) Disconnect the battery negative cables. (2) Drain cooling system until coolant
is below thermostat (Refer to 7 - COOLING - STAN- DARD PROCEDURE).
level
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 a matching number or letter.
(3) Remove radiator hose clamp and hose from
thermostat housing.
(4) Remove the three (3) water outlet-to-cylinder head bolts and remove the water outlet connector (Fig. 28).
(5) Clean the mating surfaces of the water outlet connector and clean the thermostat seat groove at the top of the thermostat housing (Fig. 28).
INSTALLATION
Replace if damaged.
with water.
able heating device.
(4) Place the container on a hot plate or other suit-
(1) Inspect
thermostat seal
for cuts or nicks.
(5) Place a commercially available radiator ther-
mometer into the water.
(6) Apply heat to the water while observing the
thermostat and thermometer.
(7) The thermostat will begin to open at 85.5 — 89.4°C. (186 —193°F ). If the valve starts to move before this temperature is reached, it is opening too early. Replace thermostat. The thermostat should be fully open (valve will stop moving) at 97°C (207°F). If
(2) Install the thermostat into the groove in the
top of the cylinder head (Fig. 28).
(3) Install
the thermostat housing and bolts.
Tighten the bolts to 10 N·m (88 in. lbs.) torque. (4) Install the radiator upper hose and clamp. (5) Fill the cooling system with coolant (Refer to 7
- COOLING - STANDARD PROCEDURE). (6) Connect the battery negative cables.
ENGINE
7 - 54
ENGINE COOLANT THERMOSTAT - 5.9L DIESEL (Continued)DR
Fig.28ThermostatRemoval/Installation
1 - THERMOSTAT HOUSING 2 - CYLINDER HEAD 3 - THERMOSTAT
(7) Start the engine and check for coolant leaks. Run engine to check for proper thermostat operation.
FAN DRIVE VISCOUS CLUTCH DESCRIPTION
The thermal viscous fan drive (Fig. 29) is a sili- cone-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 speeds while limiting the top speed of the fan to a predetermined maximum level at higher engine speeds.
OPERATION
A thermostatic bimetallic spring coil is located on the front face of the viscous fan drive unit (a typical viscous unit is shown in (Fig. 30). 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.
Only when sufficient heat is present, will the vis- cous fan drive 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.
Fig.29ViscousFan
1 - WATER PUMP BYPASS HOSE 2 - FAN BLADE ASSEMBLY 3 - VISCOUS FAN DRIVE 4 - WATER PUMP AND PULLEY
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.
Fig.30ViscousFanDrive—Typical
1 - VISCOUS FAN DRIVE 2 - THERMOSTATIC SPRING 3 - MOUNTING NUT TO WATER PUMP HUB
DIAGNOSIS AND TESTING - VISCOUS FAN DRIVE
NOISE
NOTE: It is normal for fan noise to be louder (roar- ing) when:
† The underhood temperature is above the engage- ment point for the viscous drive coupling. This may
DR FAN DRIVE VISCOUS CLUTCH (Continued)
occur when ambient (outside air temperature) is very high.† Engine loads and temperatures are high such as when towing a trailer. † Cool silicone fluid within the fan drive unit is being redistributed back to its normal disengaged (warm) position. This can occur during the first 15
seconds to one minute after engine start-up on a cold engine.LEAKS
Viscous fan drive operation is not affected by small oil stains near the drive bearing. If leakage appears excessive, replace the fan drive unit.
VISCOUS 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. The timing light is to be used as a strobe light. This step cannot be used on the diesel engine.
(4) Block the air flow through the radiator. Secure a sheet of plastic in front of the radiator. 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.
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 start to occur at/be- tween:† 3.7L Automatic — 93° C - 99°C (200° F - 210° F)
ENGINE
7 - 55
(185° to 195° F)
† 3.7L Manual/4.7L Automatic/5.9L — 85° to 91° C † 4.7L Manual — 74° to 79° C (165° to 175° F) † Engagement is distinguishable by a definite increase in fan flow noise (roaring). The timing light also will indicate an increase in the speed of the fan. (7) When viscous drive engagement is verified, remove the plastic sheet. Fan drive disengagement should start to occur at or between: † 3.7L Automatic — 76°C to 81°C (168° F to 178° F)† 3.7L Manual/4.7L Auto/ 5.9L — 67°C to 73°C (153° F to 163° F) † 4.7L Manual — 56°C to 62°C (133° F to 143° F) † 8.0L engine — 88° to 96° C (190° to 205° F) A definite decrease of fan flow noise (roaring) should be noticed. If not, replace the defective viscous fan drive unit.
CAUTION: Some engines equipped with serpentine 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 overheating.
If
the viscous fan drive is replaced CAUTION: because of mechanical damage, the cooling fan blades should also be inspected. Inspect for fatigue cracks, loose blades, or loose rivets that could have resulted from excessive vibration. Replace fan blade assembly if any of these conditions are found. Also inspect water pump bearing and shaft assembly for any related damage due to a viscous fan drive malfunction.
FAN DRIVE VISCOUS CLUTCH - 5.9L DIESEL DESCRIPTION
The electronically controlled thermal viscous fan drive (Fig. 31) is attached to the fan drive pulley mounted to the engine. The coupling allows the fan to be driven in a normal manner. The fan speed is controlled by the electronic control module.
OPERATION
The Engine Control Module (ECM) controls the level of engagment of the electronically controlled viscous fan clutch by monitoring coolant tempera- ture, intake manifold temperature, and air condition- ing status. Based on cooling requirements, the ECM sends a signal to the viscous fan clutch to increase or decrease the fan speed.
ENGINE
7 - 56
FAN DRIVE VISCOUS CLUTCH - 5.9L DIESEL (Continued)DR
ELECTRONICALLY CONTROLLED VISCOUS 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.
The Electronic Viscous Fan drive can be tested
using the DRB III scan tool.
(1) Set the parking brake and verify the transmis-
sion is in park or neutral.
(2) Stat and allow engine to reach normal operat-
ing termeratures.
(3) With engine idling, connect the DRB III and
select appropraite model year and engine option.
(4) Lacate and select actuator tests, then select
PWM Viscous Fan.
(5) Monitor fan speed and duty cycle; verify that the fan speed increments are proportional to the duty cycle precentage during the actuation event.
Fig.31FanBlade/ViscousFanDrive
1 - ELECTRICAL CONNECTOR 2 - VISCOUS FAN DRIVE 3 - FAN BLADE 4 - BOLT 5 - FAN DRIVE
Fan speed is monitored by the ECM. A lack of fan speed will set a DTC. Circuit concerns will also set fan clutch DTC’s.
Fan speed and duty cycle percent can be monitored
with the DRB III..
DIAGNOSIS AND TESTING - ELECTRONICLY CONTOLLED VISCOUS FAN DRIVE
NOISE
NOTE: It is normal for fan noise to be louder (roar- ing) when:
when towing a trailer.
ent (outside air temperature) is very high.
† Fan duty cycle high. This may occur when ambi- † Engine loads and temperatures are high such as † Cool silicone fluid within the fan drive unit is being redistributed back to its normal disengaged (warm) position. This can occur during the first 15
seconds to one minute after engine start-up on a cold engine.LEAKS
Viscous fan drive operation is not affected by small oil stains near the drive bearing. If leakage appears excessive, replace the fan drive unit.
CAUTION: Some engines equipped with serpentine 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 overheating.
If
the viscous fan drive is replaced CAUTION: because of mechanical damage, the cooling fan blades should also be inspected. Inspect for fatigue cracks, loose blades, or loose rivets that could have resulted from excessive vibration. Replace fan blade assembly if any of these conditions are found.
RADIATOR DESCRIPTION
The radiator is a aluminum cross-flow design with horizontal tubes through the radiator core and verti- cal plastic side tanks (Fig. 32).
This radiator does not contain an internal trans-
mission oil cooler
OPERATION
The radiator supplies sufficient heat transfer using the cooling fins interlaced between the horizontal tubes in the radiator core to cool the engine.
DR RADIATOR (Continued)
Fig.32Radiator—Typical
1 - SCREW 2 - SCREW 3 - LOWER MOUNT 4 - RADIATOR 5 - DRAINCOCK 6 -LOWER MOUNT
DIAGNOSIS AND TESTING—RADIATOR COOLANT FLOW
Use the following procedure to determine if coolant
is flowing through the cooling system.
(1) Idle engine until operating temperature is reached. If the upper radiator hose is warm to the touch, the thermostat is opening and coolant is flow- ing to the radiator.
WARNING: HOT, PRESSURIZED COOLANT CAN CAUSE INJURY BY SCALDING. USING A RAG TO COVER THE RADIATOR PRESSURE CAP, OPEN RADIATOR CAP SLOWLY TO THE FIRST STOP. THIS WILL ALLOW ANY BUILT-UP PRESSURE TO VENT TO THE RESERVE/OVERFLOW TANK. AFTER PRES- SURE BUILD-UP HAS BEEN RELEASED, REMOVE CAP FROM FILLER NECK.
(2) Drain a small amount of coolant from the radi- ator until the ends of the radiator tubes are visible through the filler neck. Idle the engine at normal operating temperature. If coolant is flowing past the exposed tubes, the coolant is circulating.
REMOVAL
(1) Disconnect battery negative cables.
ENGINE
7 - 57
WARNING: DO NOT REMOVE THE CYLINDER BLOCK DRAIN PLUGS OR LOOSEN THE RADIATOR DRAINCOCK WITH THE SYSTEM HOT AND UNDER PRESSURE. SERIOUS BURNS FROM THE COOL- ANT CAN OCCUR.
(2) Drain the cooling system (Refer to 7 - COOL-
ING - STANDARD PROCEDURE).
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. ALWAYS WEAR SAFETY GLASSES WHEN SERVICING CONSTANT 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 a matching number or letter and the correct width.
(3) Remove the hose clamps and hoses from radia-
tor.
(4) Remove the coolant reserve/overflow tank hose
from the radiator filler neck. coolant
(5) Remove
reserve/overflow tank (5.9L) or the coolant degas container(3.7L/4.7L) from the fan shroud (pull straight up). The tank slips into slots on the fan shroud.
the
(6) Unclip the power steering hoses from the fan
shroud.
(7) Disconnect
the windshield washer reservoir tank and remove the tank.
the electrical connectors at
(8) Remove the fan shroud mounting bolts and pull up and out of the radiator tank clips (Fig. 33). Posi- tion shroud rearward over the fan blades towards engine.
(9) Disconnect the transmission cooler lines from the transmission cooler, then plug the transmission lines and cooler to prevent leakage.
(10) Disconnect the power steering lines from the power steering cooler, then plug the power steering lines and cooler to prevent leakage.
(11) Remove the two radiator upper mounting
bolts (Fig. 34).
(12) Lift the radiator straight up and out of the engine compartment. Take care not to damage cool- ing fins or tubes on the radiator and oil coolers when removing.
ENGINE
7 - 58
RADIATOR (Continued)Fig.33FanShroud
1 - RADIATOR 2 - SCREWS 3 - FAN SHROUD 4 - SLIDE MOUNT
Fig.34Radiator
1 - SCREW 2 - SCREW 3 - LOWER MOUNT 4 - RADIATOR 5 - DRAINCOCK 6 -LOWER MOUNT
DR
NOTE: The radiator is equipped with one alignment dowel on the bottom of the outlet tank and one retaining bracket on the front side of the inlet tank. Both features have rubber insulators attached to them that must be present. The alignment dowel fits into a hole at the bottom of the front end sheet metal vertical support post and the support bracket rests on top of the lower radiator closure tube.
CLEANING
Clean radiator fins are necessary for good heat transfer. The radiator and oil cooler fins should be cleaned when an accumulation of debris has occurred. With the engine cold, apply cold water and compressed air to the back (engine side) of the radi- ator to flush the radiator and/or oil coolers of debris.
INSPECTION
Inspect the radiator side tanks for cracks, broken or missing fittings also inspect the joint where the tanks seam up to the radiator core for signs of leak- age and/or deteriorating seals.
Inspect radiator core for corroded, bent or missing cooling fins. Inspect the core for bent or damaged cooling tubes.
INSTALLATION
(1) Position the fan shroud over the fan blades
rearward towards engine.
(2) Install the rubber insulators to the lower radi- ator mounting features (alignment dowel and support bracket at the lower part of the radiator).
(3) Lower the radiator into position while guiding the alignment dowel into the vertical post bracket. Position and seat the lower radiator support bracket onto the lower radiator closure tube.
(4) Install
the upper radiator mounting bolts.
Tighten bolts to 8.5 N·m (75 in. lbs.).
(5) Connect the lower radiator hose and install the
clamp in the proper position.
(6) Connect the power steering hoses to the power
steering oil cooler and install the clamps.
(7) Connect the transmission oil cooler lines to the transmission oil cooler and install the secondary latches.
(8) Position the fan shroud into the mounting clips on the radiator tanks and secure with bolts. Tighten the bolts to 8.5 N·m (75 in. lbs.).
(9) Secure the power steering hoses into the clip
on the lower fan shroud.
(10) Install the windshield washer reservoir tank
and connect the hose and electrical connector.
(11) Install
reserve/overflow container hose(s) to radiator filler neck and secure properly with clamps.
coolant
DR RADIATOR (Continued)
(12) Install coolant reserve/overflow container or degas container to fan shroud and tighten the bolts to 8.5 N·m (75 in. lbs.). (13) Connect upper
radiator hose and install
clamp.
(14) Install battery negative cable. (15) Fill cooling system with coolant (Refer to 7 -
COOLING - STANDARD PROCEDURE).
(16) Operate the engine until
it reaches normal operating temperature. Check cooling system fluid levels.
RADIATOR - 5.9L DIESEL DESCRIPTION
The radiator is a aluminum cross-flow design with horizontal tubes through the radiator core and verti- cal plastic side tanks (Fig. 35).
This radiator does not contain an internal trans-
mission oil cooler
Fig.35Radiator—Typical
1 - SCREW 2 - SCREW 3 - LOWER MOUNT 4 - RADIATOR 5 - DRAINCOCK 6 -LOWER MOUNT
OPERATION
The radiator supplies sufficient heat transfer using the cooling fins interlaced between the horizontal tubes in the radiator core to cool the engine.
ENGINE
7 - 59
DIAGNOSIS AND TESTING—RADIATOR COOLANT FLOW
Use the following procedure to determine if coolant
is flowing through the cooling system.
(1) Idle engine until operating temperature is reached. If the upper radiator hose is warm to the touch, the thermostat is opening and coolant is flow- ing to the radiator.
WARNING: HOT, PRESSURIZED COOLANT CAN CAUSE INJURY BY SCALDING. USING A RAG TO COVER THE RADIATOR PRESSURE CAP, OPEN RADIATOR CAP SLOWLY TO THE FIRST STOP. THIS WILL ALLOW ANY BUILT-UP PRESSURE TO VENT TO THE RESERVE/OVERFLOW TANK. AFTER PRES- SURE BUILD-UP HAS BEEN RELEASED, REMOVE CAP FROM FILLER NECK.
(2) Drain a small amount of coolant from the radi- ator until the ends of the radiator tubes are visible through the filler neck. Idle the engine at normal operating temperature. If coolant is flowing past the exposed tubes, the coolant is circulating.
REMOVAL
(1) Disconnect both battery negative cables.
WARNING: DO NOT REMOVE THE CYLINDER BLOCK DRAIN PLUGS OR LOOSEN THE RADIATOR DRAINCOCK WITH THE SYSTEM HOT AND UNDER PRESSURE. SERIOUS BURNS FROM COOLANT CAN OCCUR.
(2) Drain the cooling system (Refer to 7 - COOL-
ING - STANDARD PROCEDURE).
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 a matching number or letter.
(3) Remove air box and turbocharger inlet tube. (4) Remove coolant tank hose, washer bottle hose and the positive battery cable from the fastening clips located on top of the radiator.
(5) Remove hose clamps and hoses from radiator.
ENGINE
7 - 60
RADIATOR - 5.9L DIESEL (Continued)DR
(6) Remove the power steering cooler mounting bolts and position the power steering cooler out of the way.
(7) Disconnect the transmission cooler lines at the transmission. The transmission cooler will remain on the radiator and can be removed as an assembly.
(8) Remove the lower shroud assembly and the electronic viscous fan wiring from the upper shroud assembly.
(9) Remove the two radiator upper mounting bolts
(Fig. 36).
Fig.36FanShroudMounting—5.9LDieselEngine 1 - RADIATOR SUPPORT 2 - UPPER FAN SHROUD 3 - BOLTS (2) 4 - LOWER FAN SHROUD 5 - RADIATOR
(10) Lift radiator straight up and out of engine compartment. The bottom of the radiator is equipped with two alignment dowels that fit into holes in the lower radiator support panel. Rubber biscuits (insu- lators) are installed to these dowels. Take care not to damage cooling fins or tubes on the radiator and air conditioning condenser when removing.
CLEANING
Clean radiator fins are necessary for good heat transfer. The radiator and oil cooler fins should be cleaned when an accumulation of debris has occurred. With the engine cold, apply cold water and compressed air to the back (engine side) of the radi- ator to flush the radiator and/or oil coolers of debris.
INSPECTION
Inspect the radiator side tanks for cracks, broken or missing fittings also inspect the joint where the tanks seam up to the radiator core for signs of leak- age and/or deteriorating seals.
Inspect radiator core for corroded, bent or missing cooling fins. Inspect the core for bent or damaged cooling tubes.
INSTALLATION
(1) Install rubber insulators to alignment dowels
at lower part of radiator.
(2) Lower the radiator into position while guiding the two alignment dowels into lower radiator sup- port. Different alignment holes are provided in the lower radiator support for each engine application.
(3) Install
two upper radiator mounting bolts.
Tighten bolts to 11 N·m (95 in. lbs.) torque.
(4) Connect both radiator hoses and install hose
clamps.
(5) Connect transmission cooler lines to radiator tank. Inspect quick connect fittings for debris and install until an audible “click” is heard. Pull apart to verify connection.
(6) Position power steering cooler on the radiator
and tighten nuts to 8.5M·N (75 in. lbs.)
(7) Attach electronic viscous fan wiring to upper
shroud ands install lower shroud.
(8) Position coolant recover tank hose, washer bot- tle hose and the positive battery cable into the clips located on the top of the radiator.
(9) Install air box and turbocharger inlet hose.
Tighten clamps to 4 N·M (35 in. lbs.).
(10) Position heater controls to full heat position. (11) Fill cooling system with coolant (Refer to 7 -
COOLING - STANDARD PROCEDURE).
(12) Operate engine until it reaches normal tem- perature. Check cooling system and automatic trans- mission (if equipped) fluid levels.
RADIATOR PRESSURE CAP DESCRIPTION
All cooling systems are equipped with a pressure cap (Fig. 37). For 5.9L engines, the pressure cap is located on top of the radiator outlet tank. For the 3.7L/4.7L engines, the pressure cap is located on top of the coolant degas container. The cap releases pres- sure at some point within a range of 97-to-124 kPa (14-to-18 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 higher coolant boiling point allowing increased radi- ator cooling capacity. The cap contains a spring-
DR RADIATOR PRESSURE CAP (Continued)
loaded pressure relief valve. This valve opens when system pressure reaches the release range of 97-to- 124 kPa (14-to-18 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.
ENGINE
7 - 61
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING—RADIATOR CAP-TO-FILLER NECK SEAL
The pressure cap upper gasket (seal) pressure relief can be tested by removing overflow hose from the radiator filler neck tube. Attach the hose of the pressure tester tool 7700 (or equivalent) to the tube. It will be necessary to disconnect hose from its adapter for the filler neck. Pump air into radiator. The pressure cap upper gasket should relieve at 69
to 124kPa (10 to 18 psi) and hold pressure at a min- imum 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 the radiator cap at any time except
for the following purposes:
(1) Check and adjust antifreeze freeze point. (2) Refill the system with new antifreeze. (3) Conducting service procedures. (4) Checking for vacuum leaks.
Fig.37RadiatorPressureCap-Typical
1 - FILLER NECK SEAL 2 - VACUUM VENT VALVE 3 - PRESSURE RATING 4 - PRESSURE VALVE
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 the cooling system. This causes the vacuum valve to open and coolant in the reserve/overflow container to be drawn through the recovery hose connecting the filler neck and reserve/overflow container. If the vacuum valve is stuck shut, or the recovery hose is kinked, radiator hoses will collapse on cool down.
For the 3.7L/4.7L engine, the vacuum valve will open and relieve the vacuum pressure in the cooling system.
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/ OVERFLOW HOSE INTO RESERVE/OVERFLOW TANK. SQUEEZE RADIATOR UPPER HOSE TO DETERMINE WHEN BEEN RELEASED. WHEN COOLANT AND STEAM STOP BEING PUSHED INTO TANK AND SYSTEM PRES- SURE DROPS, REMOVE RADIATOR CAP COM- PLETELY.
PRESSURE
HAS
DIAGNOSIS AND TESTING - RADIATOR CAP
Remove the cap from the radiator. Be sure that the sealing surfaces are clean. Moisten the rubber gasket with water and install the cap on the pressure tester 7700 or an equivalent (Fig. 38).
Operate the tester pump to bring the pressure to 104 kPa (15 psi) on the gauge. If the pressure cap fails to hold pressure of at least 97 kPa (14 psi) replace the cap. Refer to the following CAUTION.
ENGINE
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RADIATOR PRESSURE CAP (Continued)DR
Fig.39RadiatorPressureCap
1 - STAINLESS-STEEL SWIVEL TOP 2 - RUBBER SEALS 3 - VENT VALVE 4 - RADIATOR TANK 5 - FILLER NECK 6 - OVERFLOW NIPPLE 7 - MAIN SPRING 8 - GASKET RETAINER
designed for a coolant reserve/overflow 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.
WATER PUMP - 5.9L DESCRIPTION
The water pump is located on the engine front cover, and has an integral pulley attached (Fig. 40). 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 for ven- tilation. The water pump seals are lubricated by antifreeze in the coolant mixture. Additional lubrica- tion is not necessary.
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.
DIAGNOSIS AND TESTING—WATER PUMP
A quick test to determine if pump is working is to check if heater warms properly. A defective water pump will not be able to circulate heated coolant through the long heater hose to the heater core.
Fig.38PressureTestingRadiatorCap-Typical
1 - PRESSURE CAP 2 - TYPICAL COOLING SYSTEM PRESSURE TESTER
The pressure cap may test properly while posi- tioned on tool 7700 (or equivalent). It may not hold pressure or vacuum when installed on the radiator. If so, inspect the radiator filler neck and radiator cap’s top gasket for damage. Also inspect for dirt or distor- tion that may prevent the cap from sealing properly.
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.
CLEANING
Use only a mild soap and water to clean the radi- ator cap. Using any type of solvent may cause dam- age to the seal in the radiator cap.
INSPECTION
