Trans temp DODGE RAM 1500 1998 2.G User Guide

Common causes of runout are:
²heat warpage
²improper machining
²incorrect bolt tightening
²improper seating on crankshaft flange shoulder
²foreign material on crankshaft flange
Flywheel machining is not recommended. The fly-
wheel clutch surface is machined to a unique contour
and machining will negate this feature. Minor fly-
wheel scoring can be cleaned up by hand with 180
grit emery or with surface grinding equipment.
Remove only enough material to reduce scoring
(approximately 0.001 - 0.003 in.). Heavy stock
removal isnot recommended.Replace the flywheel
if scoring is severe and deeper than 0.076 mm (0.003
in.). Excessive stock removal can result in flywheel
cracking or warpage after installation; it can also
weaken the flywheel and interfere with proper clutch
release.
Clean the crankshaft flange before mounting the
flywheel. Dirt and grease on the flange surface may
cock the flywheel causing excessive runout. Use new
bolts when remounting a flywheel and secure the
bolts with Mopar Lock And Seal or equivalent.
Tighten flywheel bolts to specified torque only. Over-
tightening can distort the flywheel hub causing
runout.
REMOVAL
(1) Remove transmission.
(2) Remove pressure plate and clutch.
(3) Remove flywheel bolts and remove flywheel.
DISASSEMBLY
NOTE: If the teeth are worn or damaged, the fly-
wheel should be replaced as an assembly. This is
the recommended repair. In cases where a new fly-
wheel is not readily available, (V10/Diesel Engine
only) a replacement ring gear can be installed. The
following procedure must be observed to avoid
damaging the flywheel and replacement gear.
WARNING: WEAR PROTECTIVE GOGGLES OR
SAFETY GLASSES WHILE CUTTING RING GEAR.
(1) Mark position of the old gear for alignment ref-
erence on the flywheel. Use a scriber for this pur-
pose.
(2) Remove the old gear by cutting most of the way
through it (at one point) with an abrasive cut-off
wheel. Then complete removal with a cold chisel or
punch.
ASSEMBLY
NOTE: The ring gear is a shrink fit on the flywheel.
This means the gear must be expanded by heating
in order to install it. The method of heating and
expanding the gear is extremely important. Every
surface of the gear must be heated at the same
time to produce uniform expansion. An oven or
similar enclosed heating device must be used. Tem-
perature required for uniform expansion is approxi-
mately 375É F.
CAUTION: Do not use an oxy/acetylene torch to
remove the old gear, or to heat and expand a new
gear. The high temperature of the torch flame can
cause localized heating that will damage the fly-
wheel. In addition, using the torch to heat a replace-
ment gear will cause uneven heating and
expansion. The torch flame can also anneal the
gear teeth resulting in rapid wear and damage after
installation.
WARNING: WEAR PROTECTIVE GOGGLES OR
SAFETY GLASSES AND HEAT RESISTENT GLOVES
WHEN HANDLING A HEATED RING GEAR.
(1) The heated gear must be installed evenly to
avoid misalignment or distortion.
(2)
Position and install the heated ring gear on the
flywheel with a shop press and a suitable press plates.
(3) Place flywheel on work bench and let it cool in
normal shop air. Allow the ring gear to cool down
completely before installation it on the engine.
CAUTION: Do not use water or compressed air to
cool the flywheel. The rapid cooling produced by
water or compressed air will distort or crack the
new gear.
INSTALLATION
(1) Install flywheel on the crank shaft.
(2) Install flywheel bolts and tighten to 95 N´m
(70 ft. lbs.).
(3) Install clutch.
(4) Install transmission.
PILOT BEARING
REMOVAL
(1) Remove transmission.
(2) Remove clutch disc.
(3) Use a suitable blind hole puller to remove pilot
bearing.
DRCLUTCH 6 - 11
FLYWHEEL (Continued)

COOLING
TABLE OF CONTENTS
page page
COOLING
DESCRIPTION
DESCRIPTION - COOLING SYSTEM FLOW
3.7L/4.7L/5.7L ENGINE..................1
DESCRIPTION - COOLING SYSTEM FLOW -
5.9L DIESEL..........................3
DESCRIPTION - HOSE CLAMPS...........3
OPERATION
OPERATION - COOLING SYSTEM.........5
OPERATION - HOSE CLAMPS............5
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTINGÐON-BOARD
DIAGNOSTICS (OBD)...................5
DIAGNOSIS AND TESTING - COOLING
SYSTEM - TESTING FOR LEAKS..........5
DIAGNOSIS AND TESTING - COOLING
SYSTEM DIESEL ENGINE................7
DIAGNOSIS AND TESTING - PRELIMINARY
CHECKS............................10
STANDARD PROCEDURE
STANDARD PROCEDURE - COOLANT
LEVEL CHECK........................17STANDARD PROCEDURE - COOLING
SYSTEM CLEANING/REVERSE FLUSHING . . 17
STANDARD PROCEDURE - DRAINING
COOLING SYSTEM - ALL GAS ENGINES . . . 17
STANDARD PROCEDURE - REFILLING
COOLING SYSTEM - ALL GAS ENGINES . . . 18
STANDARD PROCEDURE - DRAINING
COOLING SYSTEM 5.9L DIESEL ENGINE . . . 18
STANDARD PROCEDURE - REFILLING
COOLING SYSTEM 5.9L DIESEL ENGINE . . . 19
STANDARD PROCEDURE - ADDING
ADDITIONAL COOLANT.................19
SPECIFICATIONS
TORQUE............................19
SPECIFICATIONS -....................20
SPECIAL TOOLS
COOLING...........................20
ACCESSORY DRIVE......................21
ENGINE...............................30
TRANSMISSION.........................67
COOLING
DESCRIPTION
DESCRIPTION - COOLING SYSTEM FLOW
3.7L/4.7L/5.7L ENGINE
The cooling system regulates engine operating tem-
perature. It allows the engine to reach normal oper-
ating temperature as quickly as possible. It also
maintains normal operating temperature and pre-
vents overheating.The cooling system provides a means of heating
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 through the system. The
coolant recovery/reserve system utilizes an ambient
overflow bottle (Fig. 2).
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 (Fig. 1).
DRCOOLING 7 - 1

OPERATION
OPERATION - COOLING SYSTEM
The cooling system regulates engine operating tem-
perature. It allows the engine to reach normal oper-
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.
All engines utilize an ambient overflow bottle for
coolant recovery/reserve.
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.
OPERATION - HOSE CLAMPS
The spring type hose clamp applies constant ten-
sion on a hose connection. To remove a spring type
hose clamp, only use constant tension clamp pliers
designed to compress the hose clamp.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTINGÐON-BOARD
DIAGNOSTICS (OBD)
COOLING SYSTEM RELATED DIAGNOSTICS
The Engine Control Module (ECM) has been pro-
grammed to monitor certain cooling system compo-
nents:
²If 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.
²If an open or shorted condition has developed in
the electronically controlled viscous fan clutch circuit,
a Diagnostic Trouble Code (DTC) can be set.
²If fan speed is not detected a DTC will be set.
²Coolant temperature sensor circuit problems can
set a DTC.
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 ECM mem-
ory for eventual display to the service technician.
(Refer to 25 - EMISSIONS CONTROL - DESCRIP-
TION).
ACCESSING DIAGNOSTIC TROUBLE CODES
To read DTC's and to obtain cooling system data,
(Refer to 25 - EMISSIONS CONTROL - DESCRIP-
TION).
ERASING TROUBLE CODES
After the problem has been repaired, use the
DRBIIItscan tool to erase a DTC. Refer to the
appropriate Powertrain Diagnostic Procedures ser-
vice information for operation of the DRBIIItscan
tool.
DIAGNOSIS AND TESTING - 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 the engine until the radi-
ator upper hose is warm to the touch. Aim the com-
mercially available black light tool at the components
to be checked. If leaks are present, the black light
will cause the 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. 5).
Fig. 4 Spring Clamp Size Location
1 - SPRING CLAMP SIZE LOCATION
DRCOOLING 7 - 5
COOLING (Continued)

PRESSURE TESTER METHOD
The engine should be at normal operating temper-
ature. Recheck the system cold if the cause of coolant
loss is not located during the warm engine examina-
tion.
WARNING: HOT, PRESSURIZED COOLANT CAN
CAUSE INJURY BY SCALDING.
Carefully remove the radiator pressure cap from
the filler neck and check the coolant level. Push
down on the cap to disengage it from the stop tabs.
Wipe the inside of the filler neck and examine the
lower inside sealing seat for nicks, cracks, paint, dirt
and solder residue. Inspect the radiator-to- reserve/
overflow tank hose for internal obstructions. Insert a
wire through the hose to be sure it is not obstructed.
Inspect the cams on the outside of the filler neck.
If the cams are damaged, seating of the pressure cap
valve and tester seal will be affected.
Attach pressure tester (7700 or an equivalent) to
radiator filler neck.
Operate the tester pump to apply 103.4 kPa (15
psi) pressure to the system. If the hoses enlarge
excessively or bulges while testing, replace as neces-
sary. Observe the gauge pointer and determine the
condition of the cooling system according to following
criteria:
Holds Steady:If the pointer remains steady for
two minutes, serious coolant leaks are not present in
system. However, there could be an internal leakthat does not appear with normal system test pres-
sure. If it is certain that coolant is being lost and
leaks cannot be detected, inspect for interior leakage
or perform Internal Leakage Test. Refer to INTER-
NAL LEAKAGE INSPECTION.
Drops Slowly:Indicates a small leak or seepage
is occurring. Examine all of the connections for seep-
age or slight leakage with a flashlight. Inspect the
radiator, hoses, gasket edges and heater. Seal the
small leak holes with a Sealer Lubricant (or equiva-
lent). Repair the leak holes and inspect the system
again with pressure applied.
Drops Quickly:Indicates that serious leakage is
occurring. Examine the 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 the 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 the engine dipstick and inspect for water
globules. Also inspect the transmission dipstick for
water globules and transmission fluid cooler for leak-
age.
WARNING: WITH RADIATOR PRESSURE TESTER
TOOL INSTALLED ON RADIATOR, DO NOT ALLOW
PRESSURE TO EXCEED 145 kPa (21 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 the engine without the pressure cap on
the radiator until the thermostat opens. Attach a
Pressure Tester to the 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 Tester. Do this until indicated
pressure is within system range of 110 kPa (16 psi).
Fluctuation of the gauge pointer indicates compres-
sion or combustion leakage into cooling system.
Because the vehicle is equipped with a catalytic
converter,do notshort out cylinders to isolate com-
pression leak.
If the needle on dial of the 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
Fig. 5 Leak Detection Using Black Light - Typical
1 - TYPICAL BLACK LIGHT TOOL
7 - 6 COOLINGDR
COOLING (Continued)

DIAGNOSIS AND TESTING - RADIATOR
CAP................................58
CLEANING............................59
INSPECTION..........................59
WATER PUMP - 3.7L/4.7L
DESCRIPTION
DESCRIPTION - WATER PUMP...........59
DESCRIPTION - WATER PUMP BYPASS....59
OPERATION
OPERATIONÐWATER PUMP............60
OPERATION - WATER PUMP BYPASS.....60
REMOVAL.............................60
CLEANING............................61
INSPECTION..........................61
INSTALLATION.........................61
WATER PUMP - 5.9L DIESEL
DESCRIPTION.........................62OPERATION...........................62
DIAGNOSIS AND TESTINGÐWATER PUMP . . . 62
REMOVAL.............................62
CLEANING............................62
INSPECTION..........................62
INSTALLATION.........................62
WATER PUMP - 5.7L
REMOVAL.............................63
INSTALLATION.........................63
WATER PUMP - 8.0L
DIAGNOSIS AND TESTING - WATER PUMP . . . 63
REMOVAL.............................64
CLEANING............................66
INSPECTION..........................66
INSTALLATION.........................66
COOLANT
DESCRIPTION
DESCRIPTION - ENGINE COOLANT
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 use of aluminum cylinder blocks, cylinder
heads and water pumps requires special corrosion
protection. Only MopartAntifreeze/Coolant, 5
year/100,000 Mile Formula (ethylene-glycol base cool-
ant with corrosion inhibitors called HOAT, for Hybrid
Additive Technology) is recommended. This coolant
offers the best engine cooling without corrosion when
mixed with 50% distilled water to obtain a freeze
point of -37ÉC (-35ÉF).
The required ethylene-glycol (antifreeze) and water
mixture depends upon the climate and vehicle oper-
ating conditions. The antifreeze concentrationmust
alwaysbe a minimum of 44 percent, year-round in
all climates.If percentage is lower than 44 per-
cent, engine parts may be eroded by cavitation,
and cooling system components may be
severely damaged by corrosion.Maximum protec-
tion against freezing is provided with a 68% anti-
freeze concentration, which prevents freezing down to
-67.7É C (-90É F). A higher percentage will freeze at a
warmer temperature. Also, a higher percentage of
antifreeze can cause the engine to overheat becausethe 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
149É C (300É F). This temperature is hot enough to
melt plastic and soften solder. The increased temper-
ature can result in engine detonation. In addition,
100 percent ethylene-glycol freezes at 22É C (-8É 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 -32É C (-26É F). 5É C
higher than ethylene-glycol's freeze point. The boiling
point (protection against summer boil-over) of propy-
lene-glycol is 125É C (257ÉF)at96.5 kPa (14 psi),
compared to 128É C (263É F) for ethylene-glycol. Use
of propylene-glycol can result in boil-over or freeze-up
on a cooling system designed for ethylene-glycol. Pro-
pylene glycol also has poorer heat transfer character-
istics than ethylene glycol. This can increase cylinder
head temperatures under certain conditions.
Propylene-glycol/ethylene-glycol Mixtures can
cause the destabilization 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.
DRENGINE 7 - 31

DESCRIPTION - HOAT COOLANT
WARNING: ANTIFREEZE IS AN ETHYLENE-GLYCOL
BASE COOLANT AND IS HARMFUL IF SWAL-
LOWED OR INHALED. IF SWALLOWED, DRINK
TWO GLASSES OF WATER AND INDUCE VOMIT-
ING. IF INHALED, MOVE TO FRESH AIR AREA.
SEEK MEDICAL ATTENTION IMMEDIATELY. DO NOT
STORE IN OPEN OR UNMARKED CONTAINERS.
WASH SKIN AND CLOTHING THOROUGHLY AFTER
COMING IN CONTACT WITH ETHYLENE-GLYCOL.
KEEP OUT OF REACH OF CHILDREN. DISPOSE OF
GLYCOL BASE COOLANT PROPERLY, CONTACT
YOUR DEALER OR GOVERNMENT AGENCY FOR
LOCATION OF COLLECTION CENTER IN YOUR
AREA. DO NOT OPEN A COOLING SYSTEM WHEN
THE ENGINE IS AT OPERATING TEMPERATURE OR
HOT UNDER PRESSURE, PERSONAL INJURY CAN
RESULT. AVOID RADIATOR COOLING FAN WHEN
ENGINE COMPARTMENT RELATED SERVICE IS
PERFORMED, PERSONAL INJURY CAN RESULT.
CAUTION: Use of Propylene-Glycol based coolants
is not recommended, as they provide less freeze
protection and less corrosion protection.
The cooling system is designed around the coolant.
The coolant must accept heat from engine metal, in
the cylinder head area near the exhaust valves and
engine block. Then coolant carries the heat to the
radiator where the tube/fin radiator can transfer the
heat to the air.
The use of aluminum cylinder blocks, cylinder
heads, and water pumps requires special corrosion
protection. MopartAntifreeze/Coolant, 5
Year/100,000 Mile Formula (MS-9769), or the equiva-
lent ethylene-glycol base coolant with organic corro-
sion inhibitors (called HOAT, for Hybrid Organic
Additive Technology) is recommended. This coolant
offers the best engine cooling without corrosion when
mixed with 50% ethylene-glycol and 50% distilled
water to obtain a freeze point of -37ÉC (-35ÉF). If it
loses color or becomes contaminated, drain, flush,
and replace with fresh properly mixed coolant solu-
tion.
CAUTION: MoparTAntifreeze/Coolant, 5
Year/100,000 Mile Formula (MS-9769) may not be
mixed with any other type of antifreeze. Mixing of
coolants other than specified (non-HOAT or other
HOAT), may result in engine damage that may not
be covered under the new vehicle warranty, and
decreased corrosion protection.
COOLANT PERFORMANCE
The required ethylene-glycol (antifreeze) and water
mixture depends upon climate and vehicle operating
conditions. The coolant performance of various mix-
tures follows:
Pure Water-Water can absorb more heat than a
mixture of water and ethylene-glycol. This is for pur-
pose of heat transfer only. Water also freezes at a
higher temperature and allows corrosion.
100 percent Ethylene-Glycol-The corrosion
inhibiting additives in ethylene-glycol need the pres-
ence of water to dissolve. Without water, additives
form deposits in system. These act as insulation
causing temperature to rise to as high as 149ÉC
(300ÉF). This temperature is hot enough to melt plas-
tic and soften solder. The increased temperature can
result in engine detonation. In addition, 100 percent
ethylene-glycol freezes at -22ÉC (-8ÉF).
50/50 Ethylene-Glycol and Water-Is the recom-
mended mixture, it provides protection against freez-
ing to -37ÉC (-34ÉF). The antifreeze concentration
must alwaysbe a minimum of 44 percent, year-
round in all climates. If percentage is lower, engine
parts may be eroded by cavitation. Maximum protec-
tion against freezing is provided with a 68 percent
antifreeze concentration, which prevents freezing
down to -67.7ÉC (-90ÉF). A higher percentage will
freeze at a warmer temperature. Also, a higher per-
centage of antifreeze can cause the engine to over-
heat because specific heat of antifreeze is lower than
that of water.
CAUTION: Richer antifreeze mixtures cannot be
measured with normal field equipment and can
cause problems associated with 100 percent ethyl-
ene-glycol.
COOLANT SELECTION AND ADDITIVES
The use of aluminum cylinder blocks, cylinder
heads and water pumps requires special corrosion
protection. Only MopartAntifreeze/Coolant, 5
Year/100,000 Mile Formula (glycol base coolant with
corrosion inhibitors called HOAT, for Hybrid Organic
Additive Technology) is recommended. This coolant
offers the best engine cooling without corrosion when
mixed with 50% distilled water to obtain to obtain a
freeze point of -37ÉC (-35ÉF). If it loses color or
becomes contaminated, drain, flush, and replace with
fresh properly mixed coolant solution.
CAUTION: Do not use coolant additives that are
claimed to improve engine cooling.
7 - 32 ENGINEDR
COOLANT (Continued)

OPERATION
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 or propylene-glycol cool-
ant prevents water present in the cooling system
from freezing within temperatures indicated by mix-
ture ratio of coolant to water.
COOLANT RECOVERY
CONTAINER- GAS ENGINES
DESCRIPTION
The coolant reserve/overflow tank is mounted on
top of the fan shroud, and is made of high tempera-
ture plastic (Fig. 1).
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 coolantto 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.
REMOVAL
(1) Remove recovery hose from radiator.
(2) Remove the coolant container to fan shroud
mounting bolt.
(3) Tilt the container backward towards the engine
to disengage the mounting pin locking features and
lift the container away from the fan shroud (Fig. 1).
INSTALLATION
(1) Align the coolant container mounting pins into
the slots on the fan shroud and push the container
onto the fan shroud.
(2) Secure the container to the fan shroud with the
bolt. Tighten to 8.5N´m (75 in-lbs).
NOTE: Ensure that the locking feature on the
mounting pins has engaged.
(3) Connect the recovery hose to the radiator (Fig.
1).
RADIATOR FAN - GAS
ENGINES
REMOVAL
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.
(1) Disconnect negative battery cable from battery.
(2) Remove coolant reserve/overflow container from
fan shroud and lay aside.Do Notdisconnect 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. 3). 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 areRIGHT-
HAND.A 36 MM Fan Wrench should be used to pre-
vent pulley from rotating (Fig. 2).
Fig. 1 Coolant Recovery Bottle - Gas Engine
1 - SCREW
2 - COOLANT RECOVERY CONTAINER
3 - RADIATOR/RADIATOR CAP
4 - FAN SHROUD
DRENGINE 7 - 33
COOLANT (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)

RADIATOR-3.7L/4.7L/5.7L
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 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 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.
(5) Remove the coolant reserve/overflow tank from
the fan shroud (pull straight up). The tank slips into
slots on the fan shroud.
(6) Unclip the power steering hoses from the fan
shroud.
(7) Disconnect the electrical connectors at the
windshield washer reservoir tank and remove the
tank.
(8) Remove the fan shroud mounting bolts and pull
up and out of the radiator tank clips (Fig. 36). 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.
Fig. 36 Fan Shroud - Gas Engine
1 - RADIATOR
2 - SCREWS
3 - FAN SHROUD
4 - SLIDE MOUNT
7 - 54 ENGINEDR