belt JEEP XJ 1995 Service And User Guide

Axle shaft bearings produce noise and vibration
when worn or damaged. The noise generally changes
when the bearings are loaded. Road test the vehicle.
Turn the vehicle sharply to the left and to the right.
This will load the bearings and change the noise
level. Where axle bearing damage is slight, the noise
is usually not noticeable at speeds above 30 mph.
LOW SPEED KNOCK
Low speed knock is generally caused by a worn U-
joint or by worn side-gear thrust washers. A worn
pinion gear shaft bore will also cause low speed
knock.
VIBRATION
Vibration at the rear of the vehicle is usually
caused by a:
²Damaged drive shaft
²Missing drive shaft balance weight
²Worn, out-of-balance wheels
²Loose wheel lug nuts
²Worn U-joint
²Loose spring U-bolts
²Loose/broken springs
²Damaged axle shaft bearings
²Loose pinion gear nut
²Excessive pinion yoke run out²Bent axle shaft
Check for loose or damaged front-end components
or engine/transmission mounts. These components
can contribute to what appears to be a rear-end vi-
bration. Do not overlook engine accessories, brackets
and drive belts.
All driveline components should be examined be-
fore starting any repair.
Refer to Group 22ÐTires And Wheels for addi-
tional information involving vibration diagnosis.
DRIVELINE SNAP
A snap or clunk noise when the vehicle is shifted
into gear (or the clutch engaged), can be caused by:
²High engine idle speed
²Loose engine/transmission/transfer case mounts
²Worn U-joints
²Loose spring mounts
²Loose pinion gear nut and yoke
²Excessive ring gear backlash
²Excessive differential side gear-to-case clearance
The source of a snap or a clunk noise can be deter-
mined with the assistance of a helper. Raise the ve-
hicle on a hoist with the wheels free to rotate.
Instruct the helper to shift the transmission into
gear. Listen for the noise, a mechanics stethoscope is
helpful in isolating the source of a noise.
JFRONT SUSPENSION AND AXLE 2 - 19

This will load the bearings and change the noise
level. Where axle bearing damage is slight, the noise
is usually not noticeable at speeds above 30 mph.
LOW SPEED KNOCK
Low speed knock is generally caused by a worn
U-joint or by worn side-gear thrust washers. A worn
pinion gear shaft bore will also cause low speed knock.
VIBRATION
Vibration at the rear of the vehicle is usually
caused by a:
²Damaged drive shaft
²Missing drive shaft balance weight
²Worn, out-of-balance wheels
²Loose wheel lug nuts
²Worn U-joint
²Loose spring U-bolts
²Loose/broken springs
²Damaged axle shaft bearings
²Loose pinion gear nut
²Excessive pinion yoke run out
²Bent axle shaft
Check for loose or damaged front-end components
or engine/transmission mounts. These components
can contribute to what appears to be a rear-end vi-
bration. Do not overlook engine accessories, brackets
and drive belts.
All driveline components should be examined be-
fore starting any repair.
Refer to Group 22, Wheels and Tires for additional
information.
DRIVELINE SNAP
A snap or clunk noise when the vehicle is shifted
into gear (or the clutch engaged), can be caused by:
²High engine idle speed
²Loose engine/transmission/transfer case mounts
²Worn U-joints
²Loose spring mounts
²Loose pinion gear nut and yoke
²Excessive ring gear backlash
²Excessive side gear\ase clearance
The source of a snap or a clunk noise can be deter-
mined with the assistance of a helper. Raise the ve-
hicle on a hoist with the wheels free to rotate.
Instruct the helper to shift the transmission into
gear. Listen for the noise, a mechanics stethoscope is
helpful in isolating the source of a noise.
REAR AXLE ALIGNMENT
MEASUREMENT
The following procedure can be used to determine
if abnormal rear tire tread wear is the result of a
bent or deformed rear axle shaft.
(1) Raise both rear wheels off the surface with a
frame contact hoist.
(2) Attach a one-inch long piece of masking tape at
the center of each tire tread for use as reference marks.
(3) Rotate the rear wheels until both reference
marks face the front of the vehicle. Measure the dis-
tance between the outside edges of the two pieces of
tape. Record this measurement as the front of tire
(FTR) measurement.
(4) Rotate the rear wheels until both reference
marks face the rear of the vehicle. Measure the dis-
tance between the outside edges of the two pieces of
tape. Record this measurement as the rear of tire
(RTR) measurement.
(5) Subtract the (RTR) measurement from the
(FTR) measurement to obtain the amount of wheel
toe. The acceptable rear wheel toe-in position is 1/16
inch (1.6 mm) to 3/16 inch (4.8 mm) toe-out.
(6) Rotate the rear wheels until the reference
marks are facing downward. Measure the distance
between the outside edges of the two pieces of tape.
Record this measurement as the bottom of tire (BTR)
measurement.
(7) Average the (FTR) and the (RTR) distance mea-
surements. Subtract the (BTR) measurement from
this average distance to obtain the camber. The ac-
ceptable amount of camber is 1/16 inch to 3/32 inch
(1.6 to 2.4 mm).
(FTR + RTR) DIVIDED BY 2 (TWO) MINUS
BTR EQUALS CAMBER
If the (BTR) distance measurement is less
than the average FTR and RTR distance mea-
surement, the camber will be positive(+).If
the (BTR) distance measurement is greater
than the average FTR and RTR distance, the
camber will be negative(-).
If the toe position or camber is not acceptable, a bent
or deformed rear axle shaft is most likely the cause.
LIMITED SLIP DIFFERENTIAL
Under normal traction conditions, engine torque is di-
vided evenly. With low-traction surfaces, engine torque
is transferred to the wheel with the most tire traction.
When diagnosing a limited-slip differential the wheel
with the least traction can continue spinning.
The most common problem is a chatter noise when
turning corners. Check for incorrect or contaminated
lubricant. Replace the gear lubricant if necessary.
²With Trac-LokŸ differentials add a container of
MOPAR Trac-Lok Lubricant.
This will correct the condition in most instances. If
the chatter persists, clutch damage could have oc-
curred.
After changing the lubricant, drive the vehicle and
make 10 to 12 slow, figure-eight turns. This maneu-
ver will pump lubricant through the clutches.
3 - 10 REAR SUSPENSION AND AXLESJ

COOLING SYSTEM
CONTENTS
page page
DIAGNOSIS............................. 4
ENGINE ACCESSORY DRIVE BELTS......... 38
ENGINE BLOCK HEATER.................. 44GENERAL INFORMATION.................. 1
SERVICE PROCEDURES.................. 13
SPECIFICATIONS........................ 45
GENERAL INFORMATION
Throughout this group, references are made to par-
ticular vehicle models by alphabetical designation
(XJ or YJ) or by the particular vehicle nameplate. A
chart showing a breakdown of alphabetical designa-
tions is included in the Introduction section at the
beginning of this manual.
COOLING SYSTEM
The cooling system regulates engine operating tem-
perature. It allows the engine to reach normal oper-
ating temperature as quickly as possible, maintains
normal operating temperature and prevents over-
heating.
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 heavy duty cooling
package is available on most models. The package
consists of a radiator that has an increased number
of cooling fins. XJ models equipped with a 4.0L 6-cyl-inder engine and heavy duty cooling and/or air con-
ditioning also have an auxiliary electric cooling fan.
COOLING SYSTEM COMPONENTS
The cooling system consists of:
²A radiator
²Cooling fan (mechanical and/or electrical)
²Thermal viscous fan drive
²Fan shroud
²Radiator pressure cap
²Thermostat
²Coolant reserve/overflow system
²Transmission oil cooler (if equipped with an auto-
matic transmission)
²Coolant
²Water pump
²Hoses and hose clamps
SYSTEM COOLANT ROUTING
For cooling system flow routings, refer to Figs. 1, 2,
3or4.
JCOOLING SYSTEM 7 - 1

EXAMPLES:
²If the lamp (Figs. 5 or 6) flashes 1 time, pauses
and flashes 2 more times, a flashing Diagnostic Trou-
ble Code (DTC) number 12 is indicated. If this code is
observed, it is indicating that the battery has been
disconnected within the last 50 key-on cycles. It
could also indicate that battery voltage has been dis-
connected to the PCM. In either case, other DTC's
may have been erased.
²If the lamp flashes 1 time, pauses and flashes 7
more times, a flashing Diagnostic Trouble Code
(DTC) number 17 is indicated.
²If the lamp flashes 3 times, pauses and flashes 5
more times, a flashing Diagnostic Trouble Code
(DTC) number 35 is indicated.
After any stored DTC information has been ob-
served, the display will end with a flashing DTC
number 55. This will indicate the end of all stored in-
formation.
ERASING TROUBLE CODES
After the problem has been repaired, the DRB scan
tool must be used to erase a DTC. Refer to the ap-
propriate Powertrain Diagnostic Procedures service
manual for operation of the DRB scan tool.
DRB SCAN TOOL
For operation of the DRB scan tool, refer to the ap-
propriate Powertrain Diagnostic Procedures service
manual.
PRELIMINARY CHECKS
ENGINE COOLING SYSTEM OVERHEATING
Establish what driving conditions caused the com-
plaint. Abnormal loads on the cooling system such as
the following may be the cause.
1. PROLONGED IDLE, VERY HIGH AMBIENT
TEMPERATURE, SLIGHT TAIL WIND AT IDLE,
SLOW TRAFFIC, TRAFFIC JAMS, HIGH
SPEED, OR STEEP GRADES:
Driving techniques that avoid overheating are:
²Idle with A/C off when temperature gauge is at
end of normal range.
²Increasing engine speed for more air flow is recom-
mended.
2. TRAILER TOWING:
Consult Trailer Towing section of owners manual.
Do not exceed limits.
3. AIR CONDITIONING; ADD-ON OR AFTER
MARKET:
A maximum cooling package should have been or-
dered with vehicle if add-on or after market A/C is
installed. If not, maximum cooling system compo-
nents should be installed for model involved per
manufacturer's specifications.
4. RECENT SERVICE OR ACCIDENT REPAIR:
Determine if any recent service has been performed
on vehicle that may effect cooling system. This may
be:
²Engine adjustments (incorrect timing)
²Slipping engine accessory drive belt(s)
²Brakes (possibly dragging)
²Changed parts (incorrect water pump rotating in
wrong direction)
²Reconditioned radiator or cooling system refilling
(possibly under-filled or air trapped in system).
If investigation reveals none of the previous
items as a cause for an engine overheating com-
plaint, refer to following Cooling System Diag-
nosis charts.
These charts are to be used as a quick-reference
only. Refer to the group text for information.
Fig. 7 Data Link ConnectorÐXJ ModelsÐTypical
Fig. 8 Data Link ConnectorÐYJ ModelsÐTypical
JCOOLING SYSTEM DIAGNOSIS 7 - 5

SERVICE PROCEDURES
INDEX
page page
Auxiliary Electric Cooling FanÐXJ Models with 4.0L
6-Cylinder Engine....................... 35
Coolant................................. 20
Coolant Reserve/Overflow System............. 24
Cooling System Cleaning/Reverse Flushing...... 22
Cooling System Fans...................... 32
Cooling System Hoses..................... 32
Draining Cooling System.................... 21
Radiator Pressure Cap..................... 25
Radiators............................... 26Refilling Cooling System.................... 21
Testing Cooling System for Leaks............. 22
Thermostat.............................. 17
Transmission Oil Coolers.................... 36
Viscous Fan Drive......................... 34
Water Pump Tests......................... 13
Water PumpsÐGeneral Information............ 13
Water PumpsÐRemoval/Installation........... 14
WATER PUMPSÐGENERAL INFORMATION
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
drive belt on all engines.
The water pump impeller is pressed onto the rear
of a shaft that rotates in bearings pressed into the
housing. The housing has a small hole to allow seep-
age to escape. The water pump seals are lubricated
by the antifreeze in the coolant mixture. No addi-
tional lubrication is necessary.
CAUTION: All engines are equipped with a reverse
(counter-clockwise) rotating water pump and vis-
cous fan drive assembly. REVERSE is stamped or
imprinted on the cover of the viscous fan drive and
inner side of the fan. The letter R is stamped into
the back of the water pump impeller (Fig. 1).
Engines from previous model years, depending
upon application, may have been equipped with a for-
ward (clockwise) rotating water pump. Installation of
the wrong water pump will cause engine overheating.
A quick test to determine if the pump is working is
to check if the heater warms properly. A defective wa-
ter pump will not be able to circulate heated coolant
through the long heater hose to the heater core.
WATER PUMP TESTS
LOOSE IMPELLER
DO NOT WASTE reusable coolant. If solution is
clean, drain coolant into a clean container for reuse.
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.(1) Drain the cooling system.
(2) Loosen the fan belt(s).
(3) Disconnect the lower radiator hose from the
water pump.
(4) Bend a stiff clothes hanger or welding rod as
shown in (Fig. 2).
(5) Position the rod in the water pump inlet and
attempt to hold the impeller while turning the fan
blades. If equipped with a viscous fan drive, turn the
water pump shaft with a breaker bar and socket at-
tached to a mounting flange nut. If the impeller is
loose and can be held with the rod while the fan
blades are turning, the pump is defective. If the im-
peller turns, the pump is OK.
Connect the hose and install the coolant, or proceed
with repairs.
Fig. 1 Reverse Rotating Water PumpÐTypical
JCOOLING SYSTEM SERVICE PROCEDURES 7 - 13

The engine accessory drive belt must be removed
prior to removing the fan (if installed at pump) or
fan pulley.
(4) Remove engine drive belt as follows:
(a) Loosen two rear power steering pump mount-
ing bolts A (Fig. 5).
(b) Loosen upper pump pivot bolt B and lower
lock nut C (Figs. 6 or 7).
(c) Loosen pump adjusting bolt D (Fig. 5) until
belt can be removed.(d) Remove belt.
(5) Check condition of all pulleys.
(6) The power steering pump must be removed
from its cast mounting bracket to gain access to bolt
E. Bracket mounting bolt E is located behind the
power steering pump (Fig. 7).
(7) Remove two bolts A (Fig. 5).
(8) Remove locknut C and belt adjustment bolt D
(Figs. 6 or 7).
(9) Remove bolt B (Fig. 6). Position power steering
pump to the side. Hold pump in position with wire.
Do not disconnect hydraulic lines from pump.
(10) Remove bolts E, F and G (Fig. 7) and remove
pump mounting bracket.
Fig. 4 Fan Mounting Nuts
Fig. 5 P.S. Pump Rear Mounting BoltsÐTypical
Fig. 6 P.S. Pump Front Mounting Bolt/LocknutÐ
Typical
Fig. 7 Bracket Mounting BoltsÐTypical
JCOOLING SYSTEM SERVICE PROCEDURES 7 - 15

INSTALLATIONÐALL MODELS
(1) If pump is being replaced, install the heater
hose fitting to the pump. Use a sealant on the fitting
such as MoparŸ Thread Sealant With Teflon. Refer
to the directions on the package.
(2) Clean the gasket mating surfaces. If the origi-
nal pump is used, remove any deposits or other for-
eign material. Inspect the cylinder block and water
pump mating surfaces for erosion or damage from
cavitation.
(3) Install the gasket and water pump. The silicone
bead on the gasket should be facing the water pump.
Also, the gasket is installed dry. Tighten mounting
bolts to 30 Nzm (22 ft. lbs.) torque. Rotate the shaft
by hand to be sure it turns freely.
(4) Connect the radiator and heater hoses to the
water pump.
(5) Position water pump pulley to water pump hub.
(6) If equipped with a water pump mounted fan,
install fan and four nuts to water pump hub. If not
equipped with a water pump mounted fan, install
four pump hub bolts. Tighten bolts (or nuts) to 27
Nzm (20 ft. lbs.) torque.
(7) Position power steering pump bracket to en-
gine. Install bolts E, F and G (Fig. 7). Tighten bolts F
andGto38Nzm (28 ft. lbs.) torque. Tighten bolt E to
27 Nzm (20 ft. lbs.) torque.
(8) Position power steering pump to mounting
bracket. Install pivot bolt B (Fig. 6) finger tight. In-
stall locknut C and adjustment bolt D (Figs. 6 or 7)
finger tight.
(9) Install two adjustment bolts A (Fig. 6) finger
tight.
(10) Install idler pulley.
CAUTION: When installing the serpentine engine
accessory drive belt, the belt MUST be routed cor-
rectly. If not, the engine may overheat due to the
water pump rotating in the wrong direction. Refer to
figures 11, 12, 13 or 14 for appropriate belt routing.
You may also refer to the Belt Routing Label in the ve-
hicle engine compartment.
(11) Position drive belt to pulleys.
(12) Tighten belt adjustment bolt D (Fig. 5) to the
proper tension. Refer to the Specifications section at
the end of this group for belt tension.
(13) Tighten bolts A (Fig. 5) to 27 Nzm (20 ft. lbs.)
torque.
(14) Tighten pivot bolt B (Fig. 6) to 27 Nzm (20 ft.
lbs.) torque.
(15) Tighten locknut C (Fig. 6) to 27 Nzm (20 ft.
lbs.) torque.
(16) After the power steering pump has been tight-
ened, recheck belt tension.
(17) Fill cooling system with coolant and check for
leaks. Refer to Refilling Cooling System in this
group.(18) Connect battery cable to battery.
(19) Start and warm the engine. Check for leaks.
THERMOSTAT
DESCRIPTION AND OPERATION
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 195ÉF (90ÉC). Above this
Fig. 11 YJ Models with 4.0L Engine, and XJ Models
with 2.5L 4-Cylinder EngineÐWith A/C
Fig. 12 YJ Models With 2.5L or 4.0L Engine, and XJ
Models with 2.5L EngineÐWithout A/C
JCOOLING SYSTEM SERVICE PROCEDURES 7 - 17

CAUTION: Do not operate the engine with a spark
plug shorted for more than a minute. The catalytic
converter may be damaged.
Isolate the compression leak by shorting each
spark plug to the cylinder block. The gauge pointer
should stop or decrease vibration when spark plug
for leaking cylinder is shorted. This happens because
of the absence of combustion pressure.
COMBUSTION LEAKAGE TEST (WITHOUT
PRESSURE TESTER)
DO NOT WASTE reusable coolant. If the solution
is clean, drain the coolant into a clean container for
reuse.
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.
Drain sufficient coolant to allow for thermostat re-
moval. Refer to Thermostat Replacement. Disconnect
the water pump drive belt.
Disconnect the upper radiator hose from the ther-
mostat housing. Remove the housing and thermostat.
Install the thermostat housing.
Add coolant to the radiator to bring the level to
within 6.3 mm (1/4 in) of the top of the thermostat
housing.
CAUTION: Avoid overheating. Do not operate the
engine for an excessive period of time. Open the
draincock immediately after the test to eliminate
boil over of coolant.
Start the engine and accelerate rapidly three times
(to approximately 3000 rpm) while observing the
coolant. If internal engine combustion gases are leak-
ing into the cooling system, bubbles will appear in
the coolant. If bubbles do not appear, there is no in-
ternal combustion gas leakage.
COOLANT RESERVE/OVERFLOW SYSTEM
The system works along with the radiator pressure
cap. This is done by using thermal expansion and
contraction of the coolant to keep the coolant free of
trapped air. It provides:
²A volume for coolant expansion and contraction.
²A convenient and safe method for checking/adjust-
ing coolant level at atmospheric pressure. This is
done without removing the radiator pressure cap.
²Some reserve coolant to the radiator to cover mi-
nor 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 re-
turned to a proper level in the radiator.
The coolant reserve/overflow system consists of a
radiator mounted pressurized cap, a plastic reserve/
overflow tank (Figs. 22, 23 or 24), a tube (hose) con-
necting the radiator and tank, and an overflow tube
on the side of the tank.
Fig. 22 Reserve/Overflow TankÐYJ Models
Fig. 23 Reserve/Overflow TankÐXJ ModelsÐExcept
Right Hand Drive
7 - 24 COOLING SYSTEM SERVICE PROCEDURESJ

(10) Check and adjust automatic transmission
fluid level (if equipped).
COOLING SYSTEM HOSES
Rubber hoses route coolant to and from the radia-
tor, intake manifold and heater core. All XJ models
equipped with air conditioning have a coolant control
valve. This is located in-line with the heater core in-
let and outlet hoses. It controls coolant flow to the
heater core when the air conditioning system is in
operation.
Radiator lower hoses are spring-reinforced to pre-
vent collapse from water pump suction at moderate
and high engine speeds.
WARNING: CONSTANT TENSION HOSE CLAMPS
ARE USED ON MOST COOLING SYSTEM HOSES.
WHEN REMOVING OR INSTALLING, USE ONLY
TOOLS DESIGNED FOR SERVICING THIS TYPE OF
CLAMP, SUCH AS SPECIAL CLAMP TOOL (NUMBER
6094) (FIG. 36). SNAP-ON CLAMP TOOL (NUMBER
HPC-20) MAY BE USED FOR LARGER CLAMPS. AL-
WAYS WEAR SAFETY GLASSES WHEN SERVICING
CONSTANT TENSION CLAMPS.
CAUTION: A number or letter is stamped into the
tongue of constant tension clamps (Fig. 37). If re-
placement is necessary, use only an original equip-
ment clamp with matching number or letter.
Inspect the hoses at regular intervals. Replace
hoses that are cracked, feel brittle when squeezed, or
swell excessively when the system is pressurized.
For all vehicles: In areas where specific routing
clamps are not provided, be sure that hoses are posi-
tioned with sufficient clearance. Check clearance
from exhaust manifolds and pipe, fan blades, drive
belts and sway bars. Improperly positioned hoses can
be damaged, resulting in coolant loss and engine
overheating.Ordinary worm gear type hose clamps (when
equipped) can be removed with a straight screw-
driver or a hex socket.To prevent damage to
hoses or clamps, the hose clamps should be
tightened to 4 Nzm (34 in. lbs.) torque. Do not
over tighten hose clamps.
When performing a hose inspection, inspect the ra-
diator lower hose for proper position and condition of
the internal spring.
COOLING SYSTEM FANS
Also refer to either the Viscous Fan Drive and/or
the Auxiliary Electric Cooling FanÐXJ Models With
4.0L Engine sections for additional information.
All models are equipped with a mechanical temper-
ature controlled fan. This thermal viscous fan drive
(Fig. 38) is a torque-and-temperature-sensitive clutch
unit. It automatically increases or decreases fan
speed to provide proper engine cooling. XJ models
equipped with a 4.0L 6-cylinder engine may also
have an auxiliary electrical cooling fan. This is with
models that have air conditioning and/or heavy duty
cooling.
REMOVAL
Some engines have the mechanical fan/viscous fan
drive assembly mounted directly to the water pump
hub (Fig. 38). It may also be mounted to a hub/bear-
ing attached to an aluminum bracket on the right
front side of engine (Fig. 39).
(1) Loosen but do not remove at this time, the four
fan hub mounting nuts (Figs. 38 or 39).
Fig. 36 Hose Clamp ToolÐTypical
Fig. 37 Clamp Number/Letter Location
7 - 32 COOLING SYSTEM SERVICE PROCEDURESJ

(2) Remove accessory serpentine drive belt. Refer
to Belt Service in the Engine Accessory Drive Belt
section of this group.
(3) Some models with certain engines may require
the removal of the fan shroud to remove the viscous
fan drive. The fan shroud and fan blade/viscous fan
drive should be removed from the vehicle as one as-
sembly.
(4) Remove four fan hub mounting nuts (Figs. 38
or 39) and remove fan/viscous fan drive assembly
from vehicle.After removing fan blade/viscous fan drive assem-
bly,do notplace thermal viscous fan drive in hori-
zontal position. If stored horizontally, silicone fluid in
viscous fan drive could drain into its bearing assem-
bly and contaminate lubricant.
FAN BLADE INSPECTION
The fan blades cannot be repaired. If fan is dam-
aged, it must be replaced. Inspect fan as follows:
(1) Remove fan blade and viscous fan drive as an
assembly from the engine. Refer to preceding Re-
moval procedure.
(2) Remove fan blade assembly from viscous fan
drive unit (four bolts).
(3) Lay fan on a flat surface with leading edge fac-
ing down. With tip of blade touching flat surface, re-
place 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.
WARNING: DO NOT ATTEMPT TO BEND OR
STRAIGHTEN FAN BLADES IF NOT WITHIN SPECI-
FICATIONS.
(4) Inspect fan assembly for cracks, bends, loose
rivets or broken welds. Replace fan if any damage is
found.
CAUTION: If fan blade assembly is replaced be-
cause of mechanical damage, water pump and vis-
cous fan drive should also be inspected. These
components could have been damaged due to ex-
cessive vibration.
INSTALLATION
(1) Assemble fan blade to viscous fan drive.
Tighten mounting bolts to 27 Nzm (20 ft. lbs.) torque.
(2) Position mounting flange of fan blade/viscous
fan drive assembly onto hub. Install four nuts and
tighten to 24 Nzm (18 ft. lbs.) torque. Tighten the
first two nuts 180 degrees apart. Then tighten last
two nuts.
CAUTION: When installing a serpentine accessory
drive belt, the belt MUST be routed correctly. If not,
the engine may overheat due to the water pump ro-
tating in the wrong direction. Refer to appropriate
Engine Accessory Drive Belt Schematic in this
group for correct belt routing.
(3) Install accessory drive belts. Tension belts to
specifications. Refer to the Specifications section at
the end of this group.
Fig. 38 Water Pump Mounted Cooling Fan
Fig. 39 Bracket Mounted Cooling Fan
JCOOLING SYSTEM SERVICE PROCEDURES 7 - 33