Oil contamination indicates a leak at either the
rear main seal or transmission input shaft. Oil leak-
age produces a residue of oil on the housing interior
and on the clutch cover and flywheel. Heat buildup
caused by slippage between the cover, disc and fly-
wheel, can sometimes bake the oil residue onto the
components. The glaze-like residue ranges in color
from amber to black.
Road splash contamination means dirt/water is
entering the clutch housing due to loose bolts, hous-
ing cracks or through hydraulic line openings. Driv-
ing through deep water puddles can force water/road
splash into the housing through such openings.
Clutch fluid leaks are usually from damaged slave
cylinder push rod seals.
IMPROPER RELEASE OR CLUTCH ENGAGEMENT
Clutch release or engagement problems are caused
by wear or damage to one or more clutch compo-
nents. A visual inspection of the release components
will usually reveal the problem part.
Release problems can result in hard shifting and
noise. Items to look for are: leaks at the clutch cylin-
ders and interconnecting line; loose slave cylinder
bolts; worn/loose release fork and pivot stud; dam-
aged release bearing; and a worn clutch disc, or pres-
sure plate.
Normal condensation in vehicles that are stored or
out of service for long periods of time can generate
enough corrosion to make the disc stick to the fly-
wheel, or pressure plate. If this condition is experi-
enced, correction only requires that the disc be
loosened manually through the inspection plate open-
ing.
Engagement problems usually result in slip, chat-
ter/shudder, and noisy operation. The primary causes
are clutch disc contamination; clutch disc wear; mis-
alignment, or distortion; flywheel damage; or a com-
bination of the foregoing. A visual inspection is
required to determine the part actually causing the
problem.
CLUTCH MISALIGNMENT
Clutch components must be in proper alignment
with the crankshaft and transmission input shaft.
Misalignment caused by excessive runout or warpage
of any clutch component will cause grab, chatter and
improper clutch release.
CLUTCH COVER AND DISC RUNOUT
Check the clutch disc before installation. Axial
(face) runout of anewdisc should not exceed 0.50
mm (0.020 in.). Measure runout about 6 mm (1/4 in.)
from the outer edge of the disc facing. Obtain
another disc if runout is excessive.Check condition of the clutch before installation. A
warped cover or diaphragm spring will cause grab
and incomplete release or engagement. Be careful
when handling the cover and disc. Impact can distort
the cover, diaphragm spring, release fingers and the
hub of the clutch disc.
Use an alignment tool when positioning the disc on
the flywheel. The tool prevents accidental misalign-
ment which could result in cover distortion and disc
damage.
A frequent cause of clutch cover distortion (and con-
sequent misalignment) is improper bolt tightening.
CLUTCH FLYWHEEL RUNOUT
Check flywheel runout whenever misalignment is
suspected. Flywheel runout should not exceed 0.08
mm (0.003 in.). Measure runout at the outer edge of
the flywheel face with a dial indicator. Mount the
indicator on the rear face of the engine block.
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. However,
minor flywheel 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 crack-
ing 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 MopartLock And Seal. Tighten flywheel
bolts to specified torque only. Overtightening can dis-
tort the flywheel hub causing runout.
DIAGNOSIS CHART
The clutch inspection chart (Fig. 3) outlines items to
be checked before and during clutch installation. Use
the chart as a check list to help avoid overlooking
potential problem sources during service operations.
The diagnosis charts describe common clutch prob-
lems, causes and correction. Fault conditions are listed
at the top of each chart. Conditions, causes and correc-
tive action are outlined in the indicated columns.
The charts are provided as a convenient reference
when diagnosing faulty clutch operation.
6 - 4 CLUTCHBR/BE
CLUTCH (Continued)
COOLING
TABLE OF CONTENTS
page page
COOLING
DESCRIPTION............................1
OPERATION.............................2
DIAGNOSIS AND TESTING..................4
PRELIMINARY CHECKS...................4
ON-BOARD DIAGNOSTICS (OBD)...........4
COOLING SYSTEM LEAKS................5
COOLING SYSTEM GAS ENGINE...........7
COOLING SYSTEM DIESEL ENGINE........12
STANDARD PROCEDURE..................15
DRAINING COOLING SYSTEM - 3.9L/5.2L/
5.9L/8.0L ENGINES......................15
DRAINING COOLING SYSTEM - 5.9L
DIESEL ENGINE........................15REFILLING COOLING SYSTEM - 3.9L/5.2L/
5.9L/8.0L ENGINES......................15
REFILLING COOLING SYSTEM - 5.9L
DIESEL ENGINE........................15
ADDING ADDITIONAL COOLANT...........16
COOLANT LEVEL CHECK................16
COOLING SYSTEM CLEANING/REVERSE
FLUSHING............................16
COOLANT SELECTION-ADDITIVES.........17
SPECIFICATIONS........................17
SPECIAL TOOLS.........................18
ACCESSORY DRIVE......................19
ENGINE................................39
TRANSMISSION.........................79
COOLING
DESCRIPTIONÐCOOLING SYSTEM FLOW -
3.9L/5.2L/5.9L 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 also provides a means of heat-
ing the passenger compartment and cooling the auto-
matic transmission fluid (if equipped). The cooling
system is pressurized and uses a centrifugal water
pump to circulate coolant throughout the system.
An optional factory installed maximum duty cool-
ing package is available on most models. This pack-
age will provide additional cooling capacity forvehicles used under extreme conditions such as
trailer towing in high ambient temperatures (Fig. 1).
DESCRIPTIONÐCOOLING SYSTEM FLOW -
5.9L DIESEL
The diesel engine cooling system consists of (Fig.
2):
²Cross-flow radiator
²Belt driven water pump
²Belt driven mechanical cooling fan
²Thermal viscous fan drive
²Fan shroud
²Radiator pressure cap
²Vertically mounted thermostat
²Coolant reserve/recovery system
²Transmission oil cooler
²Coolant
BR/BECOOLING 7 - 1
hoses, gasket edges and heater. Seal small leak holes
with a Sealer Lubricant (or equivalent). Repair leak
holes and inspect system again with pressure
applied.
Drops Quickly:Indicates that serious leakage is
occurring. Examine system for external leakage. If
leaks are not visible, inspect for internal leakage.
Large radiator leak holes should be repaired by a
reputable radiator repair shop.
INTERNAL LEAKAGE INSPECTION
Remove engine oil pan drain plug and drain a
small amount of engine oil. If coolant is present in
the pan, it will drain first because it is heavier than
oil. An alternative method is to operate engine for a
short period to churn the oil. After this is done,
remove engine dipstick and inspect for water glob-
ules. Also inspect transmission dipstick for water
globules and transmission fluid cooler for leakage.
WARNING: WITH RADIATOR PRESSURE TESTER
TOOL INSTALLED ON RADIATOR, DO NOT ALLOW
PRESSURE TO EXCEED 110 KPA (20 PSI). PRES-
SURE WILL BUILD UP QUICKLY IF A COMBUSTION
LEAK IS PRESENT. TO RELEASE PRESSURE,
ROCK TESTER FROM SIDE TO SIDE. WHEN
REMOVING TESTER, DO NOT TURN TESTER MORE
THAN 1/2 TURN IF SYSTEM IS UNDER PRESSURE.
Operate engine without pressure cap on radiator
until thermostat opens. Attach a Pressure Tester to
filler neck. If pressure builds up quickly it indicates a
combustion leak exists. This is usually the result of a
cylinder head gasket leak or crack in engine. Repair
as necessary.
If there is not an immediate pressure increase,
pump the Pressure Tester. Do this until indicated
pressure is within system range of 110 kPa (16 psi).
Fluctuation of gauge pointer indicates compression or
combustion leakage into cooling system.
Because the vehicle is equipped with a catalytic
converter,do notremove spark plug cables or short
out cylinders to isolate compression leak.If the needle on dial of pressure tester does not
fluctuate, race engine a few times to check for an
abnormal amount of coolant or steam. This would be
emitting from exhaust pipe. Coolant or steam from
exhaust pipe may indicate a faulty cylinder head gas-
ket, cracked engine cylinder block or cylinder head.
A convenient check for exhaust gas leakage into
cooling system is provided by a commercially avail-
able Block Leak Check tool. Follow manufacturers
instructions when using this product.COMBUSTION LEAKAGE TESTÐWITHOUT
PRESSURE TESTER
DO NOT WASTE reusable coolant. If solution is
clean, drain coolant into a clean container for reuse.
WARNING: DO NOT REMOVE CYLINDER BLOCK
DRAIN PLUGS OR LOOSEN RADIATOR DRAIN-
COCK WITH SYSTEM HOT AND UNDER PRESSURE.
SERIOUS BURNS FROM COOLANT CAN OCCUR.
Drain sufficient coolant to allow thermostat
removal. (Refer to 7 - COOLING/ENGINE/ENGINE
COOLANT THERMOSTAT - REMOVAL). Remove
accessory drive belt (Refer to 7 - COOLING/ACCES-
SORY DRIVE/DRIVE BELTS - REMOVAL).
Add coolant to radiator to bring level to within 6.3
mm (1/4 in) of top of thermostat housing.
CAUTION: Avoid overheating. Do not operate
engine for an excessive period of time. Open drain-
cock immediately after test to eliminate boil over.
Start engine and accelerate rapidly three times, to
approximately 3000 rpm while observing coolant. If
internal engine combustion gases are leaking into
cooling system, bubbles will appear in coolant. If bub-
bles do not appear, internal combustion gas leakage
is not present.
7 - 6 COOLINGBR/BE
COOLING (Continued)
CONDITION POSSIBLE CAUSES CORRECTION
5. Pressure cap not installed tightly. If cap
is loose, boiling point of coolant will be
lowered. Also refer to the following Step
6.5. Tighten cap
6. Poor seals at the radiator cap. 6. (a) Check condition of cap and cap
seals. Refer to Radiator Cap. Replace
cap if necessary.
(b) Check condition of radiator filler neck.
If neck is bent or damaged, replace
radiator.
7. Coolant level low in radiator but not in
coolant reserve/overflow tank. This
means the radiator is not drawing coolant
from the coolant reserve/overflow tank as
the engine cools7. (a) Check condition of radiator cap and
cap seals. Refer to Radiator Cap in this
Group. Replace cap if necessary.
(b) Check condition of radiator filler neck.
If neck is bent or damaged, replace
radiator.
(c) Check condition of the hose from the
radiator to the coolant tank. It should fit
tight at both ends without any kinks or
tears. Replace hose if necessary.
(d) Check coolant reserve/overflow tank
and tanks hoses for blockage. Repair as
necessary.
8. Incorrect coolant concentration 8. Check coolant. (Refer to
LUBRICATION & MAINTENANCE/FLUID
TYPES - DESCRIPTION).
9. Coolant not flowing through system 9. Check for coolant flow at radiator filler
neck with some coolant removed, engine
warm and thermostat open. Coolant
should be observed flowing through
radiator. If flow is not observed, determine
area of obstruction and repair as
necessary.
10. Radiator or A/C condenser fins are
dirty or clogged.10. Remove insects and debris. (Refer to
7 - COOLING - STANDARD
PROCEDURE).
11. Radiator core is corroded or plugged. 11. Have radiator re-cored or replaced.
12. Aftermarket A/C installed without
proper radiator.12. Install proper radiator.
13. Fuel or ignition system problems. 13. Refer to 14 - Fuel System or 8 -
Electrical for diagnosis and testing
procedures.
14. Dragging brakes. 14. Check and correct as necessary.
(Refer to 5 - BRAKES - DIAGNOSIS AND
TESTING) for correct procedures.
15. Bug screen or cardboard is being
used, reducing airflow.15. Remove bug screen or cardboard.
7 - 8 COOLINGBR/BE
COOLING (Continued)
CONDITION POSSIBLE CAUSES CORRECTION
16. Thermostat partially or completely
shut.16. Check thermostat operation and
replace as necessary. (Refer to 7 -
COOLING/ENGINE/ENGINE COOLANT
THERMOSTAT - REMOVAL) .
17. Viscous fan drive not operating
properly.17. Check fan drive operation and replace
as necessary. (Refer to 7 - COOLING/
ENGINE/FAN DRIVE VISCOUS CLUTCH
- REMOVAL) .
18. Cylinder head gasket leaking. 18. Check for cylinder head gasket leaks.
(Refer to 7 - COOLING - DIAGNOSIS
AND TESTING).
19. Heater core leaking. 19. Check heater core for leaks. (Refer to
24 - HEATING & AIR CONDITIONING/
PLUMBING - DIAGNOSIS AND
TESTING). Repair as necessary.
TEMPERATURE
GAUGE READING IS
INCONSISTENT
(FLUCTUATES,
CYCLES OR IS
ERRATIC)1. During cold weather operation, with the
heater blower in the high position, the
gauge reading may drop slightly.1. A normal condition. No correction is
necessary.
2. Temperature gauge or engine mounted
gauge sensor defective or shorted. Also,
corroded or loose wiring in this circuit.2. Check operation of gauge and repair if
necessary. (Refer to 8 - ELECTRICAL/
INSTRUMENT CLUSTER - DIAGNOSIS
AND TESTING).
3. Gauge reading rises when vehicle is
brought to a stop after heavy use (engine
still running)3. A normal condition. No correction is
necessary. Gauge should return to normal
range after vehicle is driven.
4. Gauge reading high after re-starting a
warmed up (hot) engine.4. A normal condition. No correction is
necessary. The gauge should return to
normal range after a few minutes of
engine operation.
5. Coolant level low in radiator (air will
build up in the cooling system causing
the thermostat to open late).5. Check and correct coolant leaks. (Refer
to 7 - COOLING - DIAGNOSIS AND
TESTING).
6. Cylinder head gasket leaking allowing
exhaust gas to enter cooling system
causing a thermostat to open late.6. (a) Check for cylinder head gasket
leaks. (Refer to 7 - COOLING -
DIAGNOSIS AND TESTING).
(b) Check for coolant in the engine oil.
Inspect for white steam emitting from the
exhaust system. Repair as necessary.
7. Water pump impeller loose on shaft. 7. Check water pump and replace as
necessary. (Refer to 7 - COOLING/
ENGINE/WATER PUMP - REMOVAL).
8. Loose accessory drive belt. (water
pump slipping)8. (Refer to 7 - COOLING/ACCESSORY
DRIVE/DRIVE BELTS - DIAGNOSIS AND
TESTING). Check and correct as
necessary.
9. Air leak on the suction side of the
water pump allows air to build up in
cooling system causing thermostat to
open late.9. Locate leak and repair as necessary.
BR/BECOOLING 7 - 9
COOLING (Continued)
REMOVAL
WARNING: BECAUSE OF HIGH SPRING PRES-
SURE, DO NOT ATTEMPT TO DISASSEMBLE AUTO-
MATIC TENSIONER. UNIT IS SERVICED AS AN
ASSEMBLY (EXCEPT FOR PULLEY).
(1) Remove accessory drive belt. (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(2) Disconnect wiring and secondary cable from
ignition coil.
(3) Remove ignition coil from coil mounting
bracket (two bolts). Do not remove coil mounting
bracket from cylinder head.
(4) Remove tensioner assembly from mounting
bracket (one nut) (Fig. 2).(5) Remove pulley bolt. Remove pulley from ten-
sioner.
INSTALLATION
(1) Install pulley and pulley bolt to tensioner.
Tighten bolt to 61 N´m (45 ft. lbs.) torque.
(2) Install tensioner assembly to mounting
bracket. An indexing tab is located on back of ten-
sioner. Align this tab to slot in mounting bracket.
Tighten nut to 67 N´m (50 ft. lbs.) torque.
(3) Connect all wiring to ignition coil.
CAUTION: To prevent damage to coil case, coil
mounting bolts must be torqued.
(4) Install coil to coil bracket. If nuts and bolts are
used to secure coil to coil bracket, tighten to 11 N´m
(100 in. lbs.) torque. If coil mounting bracket has
been tapped for coil mounting bolts, tighten bolts to 5
N´m (50 in. lbs.) torque.
(5) Install drive belt. (Refer to 7 - COOLING/AC-
CESSORY DRIVE/DRIVE BELTS - INSTALLA-
TION).
(6) Check belt indexing marks (Fig. 2).
BELT TENSIONERS - 8.0L
DESCRIPTION
CAUTION: Do not attempt to check belt tension with
a belt tension gauge on vehicles equipped with an
automatic belt tensioner.
Drive belts on 8.0L engines are equipped with a
spring loaded automatic belt tensioner (Fig. 3). This
belt tensioner will be used with all belt configura-
tions, such as with or without power steering or air
conditioning.
The tensioner is equipped with an indexing arrow
(Fig. 4) on back of tensioner and an indexing mark
on tensioner housing.
OPERATION
WARNING: THE AUTOMATIC BELT TENSIONER
ASSEMBLY IS SPRING LOADED. DO NOT ATTEMPT
TO DISASSEMBLE THE TENSIONER ASSEMBLY.
The automatic belt tensioner maintains correct belt
tension using a coiled spring within the tensioner
housing. The spring applies pressure to the tensioner
arm pressing the arm into the belt, tensioning the
belt.Fig. 2 Tensioner Indexing Marks and Mounting Nut
1 - TENSIONER ASSEMBLY
2 - TENSIONER MOUNTING NUT
3 - INDEXING ARROW
4 - INDEXING MARK
7 - 20 ACCESSORY DRIVEBR/BE
BELT TENSIONERS - 3.9L/5.2L/5.9L (Continued)
BELT TENSIONERS - 5.9L
DIESEL
DESCRIPTION
Drive belts on all engines are equipped with a
spring loaded automatic belt tensioner (Fig. 9). This
tensioner maintains constant belt tension at all times
and requires no maintenance or adjustment.
CAUTION: Do not attempt to check belt tension with
a belt tension gauge on vehicles equipped with an
automatic belt tensioner.
OPERATION
WARNING: THE AUTOMATIC BELT TENSIONER
ASSEMBLY IS SPRING LOADED. DO NOT ATTEMPT
TO DISASSEMBLE THE TENSIONER ASSEMBLY.
The automatic belt tensioner maintains correct belt
tension using a coiled spring within the tensioner
housing. The spring applies pressure to the tensioner
arm pressing the arm into the belt, tensioning the
belt.
If a new belt is being installed, the arrow must be
within approximately 3 mm (1/8 in.) of indexing
mark. Belt is considered new if it has been used 15
minutes or less. If this specification cannot be met,
check for:
²The wrong belt being installed (incorrect length/
width)
²Worn bearings on an engine accessory (A/C com-
pressor, power steering pump, water pump, idler pul-
ley or generator)
²A pulley on an engine accessory being loose
²Misalignment of an engine accessory
²Belt incorrectly routed.
REMOVAL
WARNING: BECAUSE OF HIGH SPRING PRES-
SURE, DO NOT ATTEMPT TO DISASSEMBLE AUTO-
MATIC TENSIONER. UNIT IS SERVICED AS AN
ASSEMBLY.
(1) Remove accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(2) Remove tensioner mounting bolt (Fig. 10) and
remove tensioner.
INSTALLATION
(1) Install tensioner assembly to mounting
bracket. A dowel is located on back of tensioner. Align
this dowel to hole in tensioner mounting bracket.
Tighten bolt to 41 N´m (30 ft. lbs.) torque.
(2) Install drive belt (Refer to 7 - COOLING/AC-
CESSORY DRIVE/DRIVE BELTS - INSTALLA-
TION).
Fig. 8 Tensioner Dowel Hole
1 - DOWEL PIN HOLE
2 - TENSIONER MOUNTING BRACKET
Fig. 9 Belt
1 - WATER PUMP
2 - ACCESSORY DRIVE BELT
3 - AUTOMATIC BELT TENSIONER
4 - 3/89SQUARE BOLT
5 - MOUNT. BOLT
BR/BEACCESSORY DRIVE 7 - 23
BELT TENSIONERS - 8.0L (Continued)
The complete assembly must be removed in order
to service either pump. However, the power steering
pump can be removed and serviced separately when
necessary.
The vacuum pump is not a serviceable component.
If diagnosis indicates a pump malfunction, the pump
must be replaced as an assembly. Do not disassemble
or attempt to repair the pump.
The combined vacuum and steering pump assem-
bly must be removed for access to either pump. How-
ever, the vacuum pump can be removed without
having to disassemble the power steering pump.
If the power steering pump requires service, simply
remove the assembly and separate the two pumps.
Refer to the pump removal and installation proce-
dures in this section.
OPERATION
Vacuum pump output is transmitted to the
HEVAC, speed control, systems through a supply
hose. The hose is connected to an outlet port on the
pump housing and uses an in-line check valve to
retain system vacuum when vehicle is not running.
Pump output ranges from a minimum of 8.5 to 25
inches vacuum.
The pump rotor and vanes are rotated by the pump
drive gear. The drive gear is operated by the cam-
shaft gear.
DIAGNOSIS AND TESTINGÐVACUUM PUMP
OUTPUT
The vacuum pump supplies necessary vacuum to
components in the following systems:
²HEVAC system
²Speed Control System
A quick check to determine if the vacuum pump is
the cause of the problem in any of these systems is to
road test the vehicle and verify that all of these sys-
tems are fuctioning properly. If only one of these has
a vacuum related failure, then it is likely the vacuum
pump is not the cause.
A standard vacuum gauge can be used to check
pump output when necessary. Simply disconnect the
pump supply hose and connect a vacuum gauge to
the outlet port for testing purposes. With the engine
running, vacuum output should be a minimum of 25
inches, depending on engine speed.
DIAGNOSING LOW VACUUM OUTPUT CONDITION
If the vacuum pump is suspected of low vacuum
output, check the pump and vacuum harnesses as
follows:
(1) Visually inspect the vacuum harness for obvi-
ous failures (i.e. disconnected, cracks, breaks etc.)
(2) Disconnect the vacuum supply hose at the vac-
uum pump check valve. Connect vacuum gauge to
this valve and run engine at various throttle open-
ings. Output should be a minimum 25 inches of vac-
uum. If vacuum is consistently below 25 inches, the
vacuum pump should be replaced. If output is within
specified limits, the vacuum harness should be sus-
pected as the cause.
(3) Disconnect and isolate the vacuum supply har-
ness. Cap off open ends and apply roughly 15 inches
of vacuum to the harness. If the vacuum gauge does
not hold its reading, then there is an open in the har-
ness and it should be repaired or replaced.
(4) If the vacuum loss is still not detected at this
point, then the pump and harness are not the cause
of the low vacuum condition. Apply vacuum to the
related components of the vacuum supply system (i.e.
valves, servos, solenoids, etc.) to find the source of
the vacuum loss.
REMOVAL
(1) Disconnect battery negative cables.
(2) Position drain pan under power steering pump.
(3) Disconnect vacuum and steering pump hoses.
(4) Disconnect lubricating oil feed line from fitting
at underside of vacuum pump (Fig. 24).
(5) Remove lower bolt that attaches pump assem-
bly to engine block (Fig. 25).
Fig. 23 Diesel Vacuum & Power Steering Pump
Assembly
1 - VACUUM PUMP
2 - POWER STEERING PUMP
3 - PUMP ADAPTER
4 - DRIVE GEAR
BR/BEACCESSORY DRIVE 7 - 35
VACUUM PUMP - 5.9L DIESEL (Continued)