air DODGE RAM 1500 1998 2.G Manual Online

²Engine loads and temperatures are high such as
when towing a trailer.
²Cool 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 -18É-to-
105ÉC (0É-to-220É 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)
and blowe fan 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 88É C (190É F).
Fan driveengagementshould start to occur at/be-
tween:
²3.7L Automatic - 93É C - 99ÉC (200É F - 210É F)
²3.7L Manual/4.7L Automatic/5.9L - 85É - 91É C
(185É - 195É F)
²4.7L Manual - 74É - 79É C (165É - 175É F)
²5.7L
²5.9L
²Engagement is distinguishable by a definite
increasein 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 drivedisengagement
should start to occur at or between:
²3.7L Automatic - 76ÉC - 81ÉC (168É F - 178É F)
²3.7L Manual/4.7L Auto/ 5.9L - 67ÉC - 73ÉC (153É
F - 163É F)
²4.7L Manual - 56ÉC - 62ÉC (133É F - 143É F)
²5.7L
²5.9L
²8.0L engine - 93É to 101É C (190É - 205É F) Min-
imum 73ÉC (163ÉF). A definitedecreaseof 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.
Fig. 32 Viscous Fan Drive - Typical
1 - VISCOUS FAN DRIVE
2 - THERMOSTATIC SPRING
3 - MOUNTING NUT TO WATER PUMP HUB
DRENGINE 7 - 51
FAN DRIVE VISCOUS CLUTCH-GAS ENGINES (Continued)

CAUTION: If the viscous fan drive is replaced
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 viscous fan drive (Fig.
34) and (Fig. 33)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 engagement 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 ECMsends a signal to the viscous fan clutch to increase or
decrease the fan speed.
Fan speed is monitored by the ECM. Fan speeds
above or below a calibrated threshold will set a DTC.
Circuit concerns will also set fan clutch DTC's.
DIAGNOSIS AND TESTING - ELECTRONICALLY
CONTROLLED VISCOUS FAN DRIVE
NOISE
NOTE: It is normal for fan noise to be louder (roar-
ing) when:
²Fan duty cycle high. This may occur when ambi-
ent (outside air temperature) is very high.
²Engine loads and temperatures are high such as
when towing a trailer.
²Aggressive engine braking down a steep grade
where transmission temperatures may be high
²Cool 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.
Fig. 33 Electronically Controlled Viscous Drive
1 - ELECTRONICALLY CONTROLLED VISCOUS FAN DRIVE
2 - MOUNTING NUT
3 - WIRING SUPPORT BRACKET
4 - ELECTRICAL CONNECTOR
Fig. 34 Fan Blade/Viscous Fan Drive - 5.9L Diesel
Engine
1 - ELECTRICAL CONNECTOR
2 - VISCOUS FAN DRIVE
3 - FAN BLADE
4 - BOLT (6)
5 - RADIATOR FAN PULLEY
7 - 52 ENGINEDR
FAN DRIVE VISCOUS CLUTCH-GAS ENGINES (Continued)

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.
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), do not replace the fan drive. This
spin test must be performed when the engine is cool.
If the fan assembly does not free-wheel and a
metallic grinding sound exists, replace the electroni-
cally controlled fan drive (Refer to 7 - COOLING/EN-
GINE/RADIATOR FAN - REMOVAL).
NOTE: The following test may take up to 15 minutes
to perform.
The engine should be at normal operating temper-
ature.
(1) Set the parking brake and verify the transmis-
sion is in park or neutral.
(2) Set air conditioner (if equipped) and blower fan
to OFF.
(3) Start and allow engine to reach normal operat-
ing temperatures.
(4) Stop engine, connect the DRB III and select
appropriate model year and engine option.
(5) Check for and correct existing DTC's
(6) Using Tool 6801, connect pin 1 of the electron-
ically controlled viscous fan drive connector, located
at the lower fan shroud to battery ground (Fig. 35).
(7) Using the DRB III, verify that DTC 0480 set.
(8) Start the engine.
(9) Go to the SENSOR screen and observe the fan
speed.
(10) Run the engine at 2500 rpm.
NOTE: It maybe take 15 minutes before fan speed
increases.
(11) The fan speed should increase according to
the table below.
(12) If fan speed does not increase, replace the
electronically control viscous fan drive.
ELECTRONICALLY CONTROLLED VISCOUS FAN
DRIVE SPEEDS
ENGINE RPM FAN RPM(Min)
500 490
1000 950
1500 1420
2000 1850
2500 2230
3000 2440
(13) If the fan speed does increase and there is
still a concern, refer to the appropriate Powertrain
Diagnosis Manual to diagnosis the electronically con-
trolled viscous fan drive control circuit.
CAUTION: If the viscous fan drive is replaced
because of mechanical damage, the cooling fan
blades should also be inspected. Inspect for fatigue
cracks or chips that could result in excessive vibra-
tion. Replace fan blade assembly if any of these
conditions are found.
Fig. 35 Electronically Controlled Viscous Fan Drive
Connector
1 - ELECTRONICALLY CONTROLLED VISCOUS FAN DRIVE
CONNECTOR
2 - TOOL 6801
3 - PIN 1
DRENGINE 7 - 53
FAN DRIVE VISCOUS CLUTCH - 5.9L DIESEL (Continued)

(11) Remove the two radiator upper mounting
bolts (Fig. 37).
(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.
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, and bro-
ken or missing fittings. 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 10 N´m (90 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 coolant reserve/overflow container
hose(s) to radiator filler neck and secure properly
with clamps.
(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.
Fig. 37 Radiator
1 - SCREW
2 - SCREW
3 - LOWER MOUNT
4 - RADIATOR
5 - DRAINCOCK
6 -LOWER MOUNT
DRENGINE 7 - 55
RADIATOR-3.7L/4.7L/5.7L (Continued)

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. 38).
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.
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 (NUMBER6094). 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.
(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.
(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 cooler. The transmission cooler will
remain on the radiator and can be removed as an
assembly.
(8) Disconnect the electronic viscous fan drive elec-
trical connector.
(9) Using a fastener removal tool, remove the two
push pins and the lower shroud assembly and elec-
tronic viscous fan drive wiring from the upper shroud
assembly. Position wiring out of the way. Do not
impact or damage the electronic viscous fan drive or
pull it's wiring.
(10) Using a fastener tool, remove the wiring har-
ness bracket from the upper fan shroud.
(11) Remove the two radiator upper mounting
bolts (Fig. 38).
(12) 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 or the electronic viscous fan
connector 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, and bro-
ken or missing fittings. 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.
7 - 56 ENGINEDR

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 11.8 N´m (105 in. lbs.) torque.
(4) Connect both radiator hoses and install hose
clamps.
(5) Connect transmission cooler lines to transmis-
sion cooler. Inspect quick connect fittings for debris
and install until an audible ªclickº is heard. Pull
apart to verify connection.
(6) Position power steering cooler on the radiator
and tighten nuts to 10 N´m (90 in. lbs.)
(7) Position the electronic viscous fan wiring in the
channel in the upper shroud (Fig. 39). Make sure
that the grommet seats into the channel.
(8) Install lower radiator shroud using two push
pins. Make sure the wiring viscous fan drive wiring
is not pinched.
(9) Install the wiring harness bracket to the upper
shroud.
(10) Connect the viscous fan drive wiring to the
wiring harness.(11) Install the coolant recovery container (Refer to
7 - COOLING/ENGINE/COOLANT RECOVERY
CONTAINER - INSTALLATION).
(12) Position coolant recovery tank hose, washer
bottle hose and the positive battery cable into the
clips located on the top of the radiator.
(13) Install air box and turbocharger inlet hose.
Tighten clamps to 4 N´m (35 in. lbs.).
(14) Position heater controls tofull heatposition.
(15) Fill cooling system with coolant (Refer to 7 -
COOLING - STANDARD PROCEDURE).
(16) 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. 40). For 5.9L engines, the pressure cap is
located on top of the radiator outlet tank. For all
engines, the pressure cap is located on top of the
coolant degas container. The cap releases pressure 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-
Fig. 38 Fan Shroud Mounting - 5.9L Diesel Engine
1 - RADIATOR SUPPORT
2 - UPPER FAN SHROUD
3 - BOLTS (2)
4 - LOWER FAN SHROUD
5 - RADIATOR
Fig. 39 Electronically Controlled Viscous Fan Drive
Wiring
1 - UPPER SHROUD
2 - WIRING
DRENGINE 7 - 57
RADIATOR - 5.9L DIESEL (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.
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.
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, ºDO NOT OPEN
HOTº, 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 timeexcept
for the following purposes:
²Check and adjust antifreeze freeze point.
²Refill the system with new antifreeze.
²Conducting service procedures.
²Checking 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/
OVERFLOW HOSE INTO RESERVE/OVERFLOW
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.
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. 41).
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 followingCAUTION.
Fig. 40 Radiator Pressure Cap - Typical
1 - FILLER NECK SEAL
2 - VACUUM VENT VALVE
3 - PRESSURE RATING
4 - PRESSURE VALVE
7 - 58 ENGINEDR
RADIATOR PRESSURE CAP (Continued)

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
Hold cap at eye level, right side up. The vent valve
(Fig. 42) at bottom of cap should closed. A slight
downward pull on the vent valve should open it. If
the rubber gasket has swollen and prevents vent
valve from opening, replace cap.
Hold cap at eye level, upside down. If any light can
be seen between vent valve and rubber gasket,
replace cap. A replacement cap must be the typedesigned 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 - 3.7L/4.7L
DESCRIPTION
DESCRIPTION - WATER PUMP
A centrifugal water pump circulates coolant
through the water jackets, passages, intake manifold,
radiator core, cooling system hoses and heater core.
The pump is driven from the engine crankshaft by a
single serpentine drive belt.
The water pump impeller is pressed onto the rear
of a shaft that rotates in bearings pressed into the
housing. The housing has two small holes to allow
seepage to escape. The water pump seals are lubri-
cated by the antifreeze in the coolant mixture. No
additional lubrication is necessary.
Both heater hoses are connected to fittings on the
timing chain front cover. The water pump is also
mounted directly to the timing chain cover and is
equipped with a non serviceable integral pulley (Fig.
43).
DESCRIPTION - WATER PUMP BYPASS
The 3.7L and 4.7L engine uses an internal water/
coolant bypass system. The design uses galleries in
the timing chain cover to circulate coolant during
Fig. 41 Pressure Testing Radiator Cap - Typical
1 - PRESSURE CAP
2 - TYPICAL COOLING SYSTEM PRESSURE TESTER
Fig. 42 Radiator Pressure Cap
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
DRENGINE 7 - 59
RADIATOR PRESSURE CAP (Continued)

REMOVAL
NOTE:
The water pump on all models can be removed
without discharging the air conditioning system (if
equipped).
The water pump on all gas powered engines is
bolted directly to the engine timing chain case/
cover.
On the 8.0L V-10 engine, a rubber o-ring (instead of
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
any of these conditions are found. Also check condi-
tion of the thermal viscous fan drive (Refer to 7 -
COOLING/ENGINE/FAN DRIVE VISCOUS
CLUTCH - DIAGNOSIS AND TESTING).
(1) Disconnect negative battery cable from battery.
(2) Drain cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
Do not waste reusable coolant. If solution is clean,
drain coolant into a clean container for reuse.
(3) Remove windshield washer reservoir tank from
radiator fan shroud.
(4) Remove the four fan shroud mounting bolts at
the radiator (Fig. 51). Do not attempt to remove
shroud from vehicle at this time.
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. 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.
(5) Remove radiator upper hose at radiator.
(6) The thermal viscous fan drive is threaded on to
the water pump hub shaft (Fig. 53). Remove the fan/
fan drive assembly from water pump by turning the
mounting nut counterclockwise (as viewed from
front). Threads on the fan drive areRIGHT-HAND.
A 36 MM fan wrench can be used with Tool 6958
Spanner Wrench and Adapter Pins 8346 (Fig. 52) to
prevent the pulley from rotating.
(7) If water pump is being replaced, do not unbolt
fan blade assembly (Fig. 53) from the thermal control
fan drive.
(8) Remove fan blade/fan drive and fan shroud as
an assembly from vehicle.
After removing fan blade/fan drive assembly,do
notplace the thermal viscous fan drive in the hori-
zontal position. If stored horizontally, the silicone
Fig. 51 Typical Fan Shroud Mounting
1 - RADIATOR SUPPORT
2 - RADIATOR
3 - BOLTS (4)
4 - FAN SHROUD
Fig. 52 Using Special Tool 6958 Spanner Wrench
and Adapter Pins 8346
1 - SPECIAL TOOL 6958 SPANNER WRENCH WITH ADAPTER
PINS 8346
2-FAN
7 - 64 ENGINEDR
WATER PUMP - 8.0L (Continued)

TRANSMISSION
TABLE OF CONTENTS
page page
TRANS COOLER
DESCRIPTION.........................67
OPERATION...........................67
REMOVAL.............................68
INSTALLATION.........................68
TRANS COOLER - 5.9L DIESEL
DESCRIPTION.........................68
OPERATION...........................69REMOVAL
REMOVAL - AIR TO OIL COOLER.........69
REMOVAL - WATER TO OIL COOLER......69
DISASSEMBLY - 5.9L DIESEL ONLY.........70
ASSEMBLY - 5.9L DIESEL ONLY...........70
INSTALLATION
INSTALLATION - AIR TO OIL COOLER.....70
INSTALLATION - WATER-TO-AIR COOLER . . 70
TRANS COOLER
DESCRIPTION
An air-to-oil transmission oil cooler is standard on
all engine packages. The transmission oil cooler is
mounted to the front of the radiator above the power
steering cooler (Fig. 1) and (Fig. 2)
OPERATION
Transmission oil is routed through the cooler
where heat is removed from the transmission oil
before returning to the transmission.
Fig. 1 Cooling Module - 3.7L/4.7L/5.7L
1 - TRANS OIL COOLER
2 - LOCATING TABS
3 - POWER STEERING OIL COOLER
4 - POWER STEERING OIL COOLER MOUNTING BOLT
5 - TRANS OIL COOLER OUTLET
6 - TRANS OIL COOLER INLET
7 - COOLER LINE CLIP
8 - COOLER LINE CLIP
9 - MOUNTING BOLT
10 - RADIATOR
Fig. 2 COOLING MODULE - 5.9L GAS
1 - TRANS OIL COOLER BYPASS (5.9L only)
2 - OIL COOLER THERMOSTATIC BYPASS VALVE (5.9L only)
3 -TRANS OIL COOLER
4 - OIL COOLER MOUNTING BOLT (4)
5 - POWER STEERING COOLER
6 - POWER STEERING COOLER MOUNTING BOLT(2)
7 - TRANS OIL COOLER OUTLET
8 - TRANS OIL COOLER INLET
9 - COOLER LINE CLIP
10 - COOLER LINE CLIP
11 - RADIATOR
DRTRANSMISSION 7 - 67