2002 JEEP LIBERTY engine coolant

RADIATOR FAN - ELECTRIC
DESCRIPTION
The fan (Fig. 12) is electrically controlled by the
powertrain control module (PCM) through the fan
control relay. This relay is located on the left wheel
house in the engine compartment.
OPERATION
The electric radiator cooling fan is controlled by
the Powertrain Control Module (PCM) through the
radiator cooling fan relay. The PCM regulates fan
operation based on input from the engine coolant
temperature sensor, battery temperature sensor,air
conditioning select switch and vehicle speed.
The fan is not energized during engine cranking
regardless of the electrical input from the tempera-
ture sensors and ,air conditioning switch. However, if
engine operation conditions warrant fan engagement,
the fan will run once engine starts.
On vehicles NOT equipped with AC:The relay
is energized when the coolant temperature is above
80É C (176É F), or battery temperature sensor above ±
12É C (10É F). It will then de-energize when coolant
temperature drops below 82É C (180É F), or batter
temperature sensor below ± 9É C ( 16É F).
Vehicles Equipped with AC:In addition to using
coolant temperature and battery temperature sensorto control cooling fan operation, the cooling fan will
also be engaged when the ,air conditioning system is
activated. The relay is also energized when, air con-
ditioning is selected and coolant temperature is
above 95É C ( 203É F), or , air conditioning is selected
and battery temperature sensor is above 41É C (106É
F). It will then de-energize when , air conditioning is
selected and coolant temperature is below 92É C
(198É F), or , air conditioning is selected and battery
temperature is below 38É C (100É F).
REMOVAL
If the fan blade is bent, warped, cracked or dam-
aged in any way, it must be replacedonlywith a
replacement fan blade.Do not attempt to repair a
damaged fan blade.
NOTE: For 3.7L Heavy Duty/Max Cool/Trailer Tow
cooling package, the vicous fan cannot be removed
seperate from the shroud. Both fan and shroud
must be removed together.
(1) Disconnect battery negative cable.
(2) Using special tool 6958 spanner wrench and
8346 adapters, remove the vicous fan from the water
pump (Fig. 13).
(3) Gently lay fan into shroud.
(4) Disconnect the electrical connector for the elec-
tric fan, then disconnect connector from shroud.
Fig. 12 Radiator Cooling Fan - Typical
1 - RADIATOR
2 - ELECTRIC COOLING FAN CONNECTOR
3 - FAN SHROUD
4 - ELECTRIC COOLING FAN
Fig. 13 Viscous Fan and Fan Drive 3.7L
1 - SPECIAL TOOL 6958 SPANNER WRENCH WITH ADAPTER
PINS 8346
2-FAN
7 - 26 ENGINEKJ

Only when sufficient heat is present, will the vis-
cous fan drive engage. This is when the air flowing
through the radiator core causes a reaction to the
bimetallic coil. It then increases fan speed to provide
the necessary additional engine cooling.
Once the engine has cooled, the radiator discharge
temperature will drop. The bimetallic coil again
reacts and the fan speed is reduced to the previous
disengaged speed.
DIAGNOSIS AND TESTING - VISCOUS FAN
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 (timing light is to be used as a strobe
light).
(4) Block the air flow through the radiator. Secure
a sheet of plastic in front of the radiator (or air con-
ditioner condenser). Use tape at the top to secure the
plastic and be sure that the air flow is blocked.
(5) Be sure that the air conditioner (if equipped) is
turned off.
WARNING: USE EXTREME CAUTION WHEN THE
ENGINE IS OPERATING. DO NOT STAND IN A
DIRECT LINE WITH THE FAN. DO NOT PUT YOUR
HANDS NEAR THE PULLEYS, BELTS OR FAN. DO
NOT WEAR LOOSE CLOTHING.
(6) Start the engine and operate at 2400 rpm.
Within ten minutes the air temperature (indicated on
the dial thermometer) should be up to 93É C (200É F).
Fan driveengagementshould have started to occur
at between 91É to 96É C (195É to 205É F). Engage-
ment is distinguishable by a definiteincreasein fan
flow noise (roaring). The timing light also will indi-
cate an increase in the speed of the fan.
(7) When the air temperature reaches 93É C (200É
F), remove the plastic sheet. Fan drivedisengage-
mentshould have started to occur at between 62É to85É C (145É to 185É F). A definitedecreaseof fan
flow noise (roaring) should be noticed. If not, replace
the defective viscous fan drive unit.
REMOVAL
(1) Disconnect negative battery cable from battery.
NOTE: The thermal viscous fan drive/fan blade
assembly is attached (threaded) to water pump hub
shaft.
(2) Remove fan blade/viscous fan drive assembly
from water pump using special tool 6958 spanner
wrench and 8346 adapters, by turning mounting nut
counterclockwise as viewed from front (Fig. 16).
Threads on viscous fan drive areRIGHT HAND.
(3) Do not attempt to remove fan/viscous fan drive
assembly from vehicle at this time.
(4) Do not unbolt fan blade assembly from viscous
fan drive at this time.
(5) Remove fan shroud to radiator bolts.
(6) Remove fan shroud and fan blade/viscous fan
drive assembly as a complete unit from vehicle.
(7) After removing fan blade/viscous fan drive
assembly,do notplace viscous fan drive in horizon-
tal position. If stored horizontally, silicone fluid in
the viscous fan drive could drain into its bearing
assembly and contaminate lubricant.
Fig. 16 Viscous Fan and Fan Drive 3.7L
1 - SPECIAL TOOL 6958 SPANNER WRENCH WITH ADAPTER
PINS 8346
2-FAN
7 - 28 ENGINEKJ
RADIATOR - FAN - VISCOUS (Continued)

CAUTION: Do not remove water pump pulley-to-wa-
ter pump bolts. This pulley is under belt tension.
(8) Remove four bolts securing fan blade assembly
to viscous fan drive.
CLEANING
Clean the fan blades using a mild soap and water.
Do not use an abrasive to clean the blades.
INSPECTION
WARNING: DO NOT ATTEMPT TO BEND OR
STRAIGHTEN FAN BLADES IF FAN IS NOT WITHIN
SPECIFICATIONS.
CAUTION: If fan blade assembly is replaced
because of mechanical damage, water pump and
viscous fan drive should also be inspected. These
components could have been damaged due to
excessive vibration.
(1) Remove fan blade assembly from viscous fan
drive unit (four bolts).
(2) Lay fan on a flat surface with leading edge fac-
ing down. With tip of blade touching flat surface,
replace fan if clearance between opposite blade and
surface is greater than 2.0 mm (.090 inch). Rocking
motion of opposite blades should not exceed 2.0 mm
(.090 inch). Test all blades in this manner.
(3) Inspect fan assembly for cracks, bends, loose
rivets or broken welds. Replace fan if any damage is
found.
INSTALLATION
(1) Assemble fan blade to viscous fan drive.
Tighten mounting bolts to 27 N´m (20 ft. lbs.) torque.
NOTE: The vicous fan and fan shroud must be
installed as an assembly.
(2) Gently lay vicous fan into fan shroud.
(3) Install the fan shroud to radiator mounting
bolts, torque bolts to (5.5N´M or 50 in´lbs).
(4) Thread the fan and fan drive onto the water
pump pulley, and tighten nut using special tool 6958
spanner wrench and 8346 adapters.
(5) Connect the electrical connector for the electric
fan.
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
rotating in the wrong direction. (Refer to 7 - COOL-
ING/ACCESSORY DRIVE/DRIVE BELTS - REMOVAL)
for correct belt routing.
WATER PUMP
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.
17).
DESCRIPTION
The 3.7L engine uses an internal water/coolant
bypass system. The design uses galleries in the tim-
ing chain cover to circulate coolant during engine
warm-up preventing the coolant from flowing
Fig. 17 Water Pump and Timing Chain Cover
1 - INTEGRAL WATER PUMP PULLEY
2 - TIMING CHAIN COVER
3 - THERMOSTAT HOUSING
4 - HEATER HOSE FITTINGS
5 - WATER PUMP
KJENGINE 7 - 29
RADIATOR - FAN - VISCOUS (Continued)

through the radiator. The thermostat uses a stub
shaft located at the rear of the thermostat to control
flow through the bypass gallery.
OPERATION - WATER PUMP
A centrifugal water pump circulates coolant
through the water jackets, passages, intake manifold,
radiator core, cooling system hoses and heater core,
this coolant absorbs the heat generated when the
engine is running. The pump is driven by the engine
crankshaft via a drive belt.
REMOVAL
The water pump on 3.7L engines is bolted directly
to the engine timing chain case cover.
(1) Disconnect negative battery cable from battery.
(2) Drain cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(3) Remove fan/viscous fan drive assembly from
water pump (Fig. 18) (Refer to 7 - COOLING/EN-
GINE/FAN DRIVE VISCOUS CLUTCH - REMOV-
AL). Do not attempt to remove fan/viscous fan drive
assembly 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). SNAP-ON CLAMP TOOL (NUMBER HPC-20)MAY BE USED FOR LARGER CLAMPS. ALWAYS
WEAR SAFETY GLASSES WHEN SERVICING CON-
STANT TENSION CLAMPS.
CAUTION: A number or letter is stamped into the
tongue of constant tension clamps. If replacement
is necessary, use only an original equipment clamp
with matching number or letter.
(4) If water pump is being replaced, do not unbolt
fan blade assembly from thermal viscous fan drive.
(5) Remove two fan shroud-to-radiator screws, Dis-
connect the coolant overflow hose.
(6) Remove upper fan shroud and fan blade/viscous
fan drive assembly from vehicle.
(7) After removing fan blade/viscous fan drive
assembly,do notplace thermal viscous fan drive in
horizontal position. If stored horizontally, silicone
fluid in viscous fan drive could drain into its bearing
assembly and contaminate lubricant.
(8) Remove accessory drive belt (Fig. 19) (Refer to
7 - COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(9) Remove lower radiator hose clamp and remove
lower hose at water pump.
(10) Remove seven water pump mounting bolts
and one stud bolt.
Fig. 18 Viscous Fan and Fan Drive 3.7L
1 - SPECIAL TOOL 6958 SPANNER WRENCH WITH ADAPTER
PINS 8346
2-FAN
Fig. 19 Automatic Belt TensionerÐ3.7L
1 - AUTOMATIC TENSIONER
2 - WATER PUMP PULLEY
7 - 30 ENGINEKJ
WATER PUMP (Continued)

COOLING - 2.4L
TABLE OF CONTENTS
page page
COOLING - 2.4L
DESCRIPTION
DESCRIPTION - COOLING SYSTEM 2.4L
ENGINE..............................1
DESCRIPTION - HOSE CLAMPS...........1
OPERATION
OPERATION - COOLING SYSTEM.........2
OPERATION - HOSE CLAMPS............2
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - ON-BOARD
DIAGNOSTICS (OBD)...................2
DIAGNOSIS AND TESTING - PRELIMINARY
CHECKS.............................2
DIAGNOSIS AND TESTING - COOLING
SYSTEM LEAKS.......................2
DIAGNOSIS AND TESTING - COOLING
SYSTEM DIAGNOSIS CHART.............5STANDARD PROCEDURE
STANDARD PROCEDURE - DRAINING
COOLING SYSTEM....................11
STANDARD PROCEDURE - REFILLING
COOLING SYSTEM....................11
STANDARD PROCEDURE - COOLING
SYSTEM - REVERSE FLUSHING..........12
SPECIFICATIONS
TORQUE............................13
SPECIAL TOOLS
COOLING...........................13
ACCESSORY DRIVE......................14
ENGINE...............................18
TRANSMISSION.........................30
COOLING - 2.4L
DESCRIPTION
DESCRIPTION - COOLING SYSTEM 2.4L
ENGINE
The cooling system consists of the following items:
²Electric cooling fan - Standard.
²Radiator
²Hot bottle pressure cap
²Thermostat
²Coolant reserve/overflow system
²Radiator in-tank transmission oil cooler (if
equipped with an automatic transmission)
²Coolant
²Water pump
²Hoses and hose clamps
DESCRIPTION - HOSE CLAMPS
The cooling system utilizes spring type hose
clamps. If a spring type clamp replacement is neces-
sary, replace with the original Mopartequipment
spring type clamp.
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) (Fig. 1). SNAP-ON CLAMP TOOL (NUMBER
HPC-20) MAY BE USED FOR LARGER CLAMPS.
ALWAYS WEAR SAFETY GLASSES WHEN SERVIC-
ING CONSTANT TENSION CLAMPS.
CAUTION: A number or letter is stamped into the
tongue of constant tension clamps. If replacement
is necessary, use only a original equipment clamp
with matching number or letter (Fig. 1).
Fig. 1 Spring Clamp Size Location
1 - SPRING CLAMP SIZE LOCATION
KJCOOLING - 2.4L 7s - 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.
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 TESTING - ON-BOARD
DIAGNOSTICS (OBD)
COOLING SYSTEM RELATED DIAGNOSTICS
The powertrain control module (PCM) has been
programmed to monitor certain cooling system com-
ponents:
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 relay circuit controlling the electric radiator fan,
a Diagnostic Trouble Code (DTC) can be set.
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 PCM 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 DRB
scan tool to erase a DTC. Refer to the appropriate
Powertrain Diagnostic Procedures service informa-
tion for operation of the DRB scan tool.
DIAGNOSIS AND TESTING - 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:
²PROLONGED IDLE
²VERY HIGH AMBIENT TEMPERATURE
²SLIGHT TAIL WIND AT IDLE
²SLOW TRAFFIC
²TRAFFIC JAMS
²HIGH SPEED
²STEEP GRADES
Driving techniques that avoid overheating are:
²Idle with A/C off when temperature gauge is at
end of normal range.
(1) TRAILER TOWING:
Consult Trailer Towing section of owners manual.
Do not exceed limits.
(2) RECENT SERVICE OR ACCIDENT REPAIR:
Determine if any recent service has been per-
formed 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, or pump
rotating in wrong direction due to belt not correctly
routed
²Reconditioned radiator or cooling system refill-
ing (possibly under filled or air trapped in system).
NOTE: If investigation reveals none of the previous
items as a cause for an engine overheating com-
plaint, refer to following Cooling System Diagnosis
charts.
These charts are to be used as a quick-reference
only. Refer to the group text for information.
DIAGNOSIS AND TESTING - COOLING SYSTEM
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 engine until radiator
upper hose is warm to touch. Aim the commercially
available black light tool at components to be
checked. If leaks are present, black light will cause
additive to glow a bright green color.
7s - 2 COOLING - 2.4LKJ
COOLING - 2.4L (Continued)

The black light can be used in conjunction with a
pressure tester to determine if any external leaks
exist (Fig. 2).
PRESSURE TESTER METHOD
The engine should be at normal operating temper-
ature. Recheck the system cold if cause of coolant
loss is not located during the warm engine examina-
tion.
WARNING: HOT, PRESSURIZED COOLANT CAN
CAUSE INJURY BY SCALDING.
Carefully remove radiator pressure cap from pres-
sure bottle and check coolant level. Push down on
cap to disengage it from stop tabs. Wipe inside of
filler neck and examine lower inside sealing seat for
nicks, cracks, paint, and dirt. Inspect radiator-to-
reserve/overflow tank hose for internal obstructions.
Insert a wire through the hose to be sure it is not
obstructed.
Inspect cams on outside of filler neck. If cams are
damaged, seating of pressure cap valve and tester
seal will be affected.
Attach pressure tester (7700 or an equivalent) to
radiator filler neck (Fig. 3).
Operate tester pump to apply 110 kPa (16 psi)
pressure to system. If hoses enlarge excessively or
bulges while testing, replace as necessary. Observe
gauge pointer and determine condition of cooling sys-
tem according to following criteria:Holds Steady:If pointer remains steady for two
minutes, serious coolant leaks are not present in sys-
tem. However, there could be an internal leak that
does not appear with normal system test pressure. If
it is certain that coolant is being lost and leaks can-
not be detected, inspect for interior leakage or per-
form Internal Leakage Test.
Drops Slowly:Indicates a small leak or seepage
is occurring. Examine all connections for seepage or
slight leakage with a flashlight. Inspect radiator,
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.
Fig. 2 Leak Detection Using Black Light - Typical
1 - TYPICAL BLACK LIGHT TOOL
Fig. 3 Pressure Testing Cooling System - Typical
1 - TYPICAL COOLING SYSTEM PRESSURE TESTER
KJCOOLING - 2.4L7s-3
COOLING - 2.4L (Continued)

WARNING: WITH RADIATOR PRESSURE TESTER
TOOL INSTALLED ON RADIATOR, DO NOT ALLOW
PRESSURE TO EXCEED 124 KPA (18 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 TEST - WITHOUT
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.
7s - 4 COOLING - 2.4LKJ
COOLING - 2.4L (Continued)