2002 JEEP LIBERTY Timing cover

CONDITION POSSIBLE CAUSES CORRECTION
BELT BROKEN (NOTE: IDENTIFY
AND CORRECT PROBLEM
BEFORE NEW BELT IS
INSTALLED)1. Excessive tension. 1. Replace belt and automatic belt
tensioner.
2. Incorrect belt. 2. Replace belt.
3. Tensile member damaged during
belt installation.3. Replace belt.
4. Severe misalignment. 4. Check and replace.
5. Bracket, pulley, or bearing failure. 5. Replace defective component
and belt.
NOISE (OBJECTIONABLE
SQUEAL, SQUEAK, OR RUMBLE
IS HEARD OR FELT WHILE
DRIVE BELT IS IN OPERATION)1. Belt slippage. 1. Replace belt or automatic belt
tensioner.
2. Bearing noise. 2. Locate and repair.
3. Belt misalignment. 3. Replace belt.
4. Belt-to-pulley mismatch. 4. Install correct belt.
BELT TENSIONERS
REMOVAL - 3.7L ENGINE
(1) Remove accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(2) Remove tensioner assembly from engine front
cover (Fig. 2).WARNING: BECAUSE OF HIGH SPRING TENSION,
DO NOT ATTEMPT TO DISASSEMBLE AUTOMATIC
TENSIONER. UNIT IS SERVICED AS AN ASSEMBLY
(EXCEPT FOR PULLEY ON TENSIONER).
(3) Remove pulley bolt. Remove pulley from ten-
sioner.
INSTALLATION - 3.7L ENGINE
(1) Install pulley and pulley bolt to tensioner.
Tighten bolt to 61 N´m (45 ft. lbs.) torque.
(2) An indexing slot is located on back of tensioner.
Align this slot to the head of the bolt on the front
cover. Install the mounting bolt. Tighten bolt to 41
N´m (30 ft. lbs.).
(3) Install drive belt (Refer to 7 - COOLING/AC-
CESSORY DRIVE/DRIVE BELTS - INSTALLA-
TION).
(4) Check belt indexing marks (Refer to 7 - COOL-
ING/ACCESSORY DRIVE/DRIVE BELTS - INSTAL-
LATION).
DRIVE BELTS - 3.7L
REMOVAL - 3.7L ENGINE
NOTE: The belt routing schematics are published
from the latest information available at the time of
publication. If anything differs between these sche-
matics and the Belt Routing Label, use the sche-
matics on Belt Routing Label. This label is located
in the engine compartment.
Fig. 2 Automatic Belt Tensioner
1 - TIMING CHAIN COVER
2 - BOLT TORQUE TO 41 N´m (30 FT LBS)
3 - AUTOMATIC BELT TENSIONER
KJACCESSORY DRIVE 7 - 17
ACCESSORY DRIVE (Continued)

The ECT sensor is a two-wire Negative Thermal
Coefficient (NTC) sensor. Meaning, as engine coolant
temperature increases, resistance (voltage) in the
sensor decreases. As temperature decreases, resis-
tance (voltage) in the sensor increases.
OPERATION
At key-on, the Powertrain Control Module (PCM)
sends out a regulated 5 volt signal to the ECT sensor.
The PCM then monitors the signal as it passes
through the ECT sensor to the sensor ground (sensor
return).
When the engine is cold, the PCM will operate in
Open Loop cycle. It will demand slightly richer air-
fuel mixtures and higher idle speeds. This is done
until normal operating temperatures are reached.
The PCM uses inputs from the ECT sensor for the
following calculations:
²for engine coolant temperature gauge operation
through CCD or PCI (J1850) communications
²Injector pulse-width
²Spark-advance curves
²ASD relay shut-down times
²Idle Air Control (IAC) motor key-on steps
²Pulse-width prime-shot during cranking
²O2 sensor closed loop times
²Purge solenoid on/off times
²EGR solenoid on/off times (if equipped)
²Leak Detection Pump operation (if equipped)
²Radiator fan relay on/off times (if equipped)
²Target idle speed
REMOVAL
2.4L
The Engine Coolant Temperature (ECT) sensor is
installed into a water jacket at left front of cylinder
head (Fig. 1).
WARNING: HOT, PRESSURIZED COOLANT CAN
CAUSE INJURY BY SCALDING. COOLING SYSTEM
MUST BE PARTIALLY DRAINED BEFORE REMOV-
ING THE COOLANT TEMPERATURE SENSOR.
(1) Partially drain cooling system.
(2) Disconnect electrical connector from sensor.
(3) Remove sensor from cylinder head.
3.7L
The Engine Coolant Temperature (ECT) sensor is
installed into a water jacket at front of intake mani-
fold near rear of generator (Fig. 2).
WARNING: HOT, PRESSURIZED COOLANT CAN
CAUSE INJURY BY SCALDING. COOLING SYSTEM
MUST BE PARTIALLY DRAINED BEFORE REMOV-
ING THE COOLANT TEMPERATURE SENSOR.(1) Partially drain cooling system.
(2) Disconnect electrical connector from sensor.
(3) Remove sensor from intake manifold.
Fig. 1 ECT AND UPPER TIMING BELT COVER/
BOLTS-2.4L
1 - UPPER TIMING BELT COVER
2 - ELECTRICAL CONNECTOR (ECT)
3 - MOUNTING BOLTS (3)
Fig. 2 MAP SENSOR / ECT SENSOR - 3.7L
1 - MOUNTING SCREWS
2 - MAP SENSOR
3 - ECT SENSOR
7 - 20 ENGINEKJ
ENGINE COOLANT TEMPERATURE SENSOR (Continued)

INSTALLATION - 3.7L ENGINE
(1) Clean mating areas of timing chain cover and
thermostat housing.
(2)
Install thermostat (spring side down) into
recessed machined groove on timing chain cover (Fig. 4).
(3) Position thermostat housing on timing chain
cover.
(4) Install two housing-to-timing chain cover bolts.
Tighten bolts to 13 N´m (115 in. lbs.) torque.
CAUTION: Housing must be tightened evenly and
thermostat must be centered into recessed groove
in timimg chain cover. If not, it may result in a
cracked housing, damaged timing chain cover
threads or coolant leaks.
(5)
Install lower radiator hose on thermostat housing.
(6) Install splash shield.
(7) Lower vehicle.
(8) Fill cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(9) Connect negative battery cable to battery.
(10) Start and warm the engine. Check for leaks.
RADIATOR
DESCRIPTION
All vehicles are equipped with a cross flow type
radiator with plastic side tanks (Fig. 5).Plastic tanks, while stronger than brass, are sub-
ject to damage by impact, such as from tools or
wrenches. Handle radiator with care.
Fig. 4 Thermostat and Thermostat Housing
1 - THERMOSTAT HOUSING
2 - THERMOSTAT LOCATION3 - THERMOSTAT AND GASKET
4 - TIMING CHAIN COVER
Fig. 5 Cross Flow Radiator - Typical
1 - RADIATOR
7 - 22 ENGINEKJ
ENGINE COOLANT THERMOSTAT (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)

CAUTION: Do not pry water pump at timing chain
case/cover. The machined surfaces may be dam-
aged resulting in leaks.
(11) Remove water pump and gasket. Discard gas-
ket.
CLEANING
Clean the gasket mating surface. Use caution not
to damage the gasket sealing surface.
INSPECTION
Inspect the water pump assembly for cracks in the
housing, Water leaks from shaft seal, Loose or rough
turning bearing or Impeller rubbing either the pump
body or timing chain case/cover.
INSTALLATION
The water pump on 3.7L engines is bolted directly
to the engine timing chain case cover.
(1) Clean gasket mating surfaces.
(2) Using a new gasket, position water pump and
install mounting bolts as shown. (Fig. 20). Tighten
water pump mounting bolts to 54 N´m (40 ft. lbs.)
torque.
(3) Spin water pump to be sure that pump impel-
ler does not rub against timing chain case/cover.
(4) Connect radiator lower hose to water pump.
(5) Relax tension from belt tensioner. Install drive
belt (Refer to 7 - COOLING/ACCESSORY DRIVE/
DRIVE BELTS - INSTALLATION).CAUTION: When installing the serpentine accessory
drive belt, belt must be routed correctly. If not,
engine may overheat due to water pump rotating in
wrong direction. Refer to (Fig. 21) for correct belt
routing. Or, refer to the Belt Routing Label located
in the engine compartment. The correct belt with
correct length must be used.
(6) Position upper fan shroud and fan blade/vis-
cous fan drive assembly.
(7) Be sure the upper and lower portions of the fan
shroud are firmly connected. All air must flow
through the radiator.
(8) Install two fan shroud-to-radiator screws.
(9) Be sure of at least 25 mm (1.0 inches) between
tips of fan blades and fan shroud.
(10) Install fan blade/viscous fan drive assembly to
water pump shaft (Refer to 7 - COOLING/ENGINE/
FAN DRIVE VISCOUS CLUTCH - INSTALLATION).
(11) Fill cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(12) Connect negative battery cable.
(13) Start and warm the engine. Check for leaks.
Fig. 20 Water Pump InstallationÐ3.7L
1 - WATER PUMP
2 - TIMING CHAIN COVER
Fig. 21 Belt Routing 3.7L
1 - GENERATOR PULLEY
2 - ACCESSORY DRIVE BELT
3 - POWER STEERING PUMP PULLEY
4 - CRANKSHAFT PULLEY
5 - IDLER PULLEY
6 - TENSIONER
7 - A/C COMPRESSOR PULLEY
8 - WATER PUMP PULLEY
KJENGINE 7 - 31
WATER PUMP (Continued)

ACCESSORY DRIVE
TABLE OF CONTENTS
page page
BELT TENSIONERS - 2.4L
REMOVAL - 2.4L ENGINE.................14
INSTALLATION - 2.4L ENGINE.............14
DRIVE BELTS -2.4L
DIAGNOSIS AND TESTING - SERPENTINE
DRIVE BELT DIAGNOSIS................15REMOVAL - 2.4L ENGINE.................16
INSTALLATION - 2.4L ENGINE.............17
BELT TENSIONERS - 2.4L
REMOVAL - 2.4L ENGINE
(1) Remove accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(2) Remove tensioner assembly from engine acces-
sory drive bracket (Fig. 1).WARNING: BECAUSE OF HIGH SPRING TENSION,
DO NOT ATTEMPT TO DISASSEMBLE AUTOMATIC
TENSIONER. UNIT IS SERVICED AS AN ASSEMBLY
(EXCEPT FOR PULLEY ON TENSIONER).
(3) Remove pulley bolt. Remove pulley from ten-
sioner.
INSTALLATION - 2.4L ENGINE
(1) Install pulley and pulley bolt to tensioner.
Tighten bolt to 61 N´m (45 ft. lbs.) torque.
(2) An indexing slot is located on back of tensioner.
Align this slot to the head of the nut on the front
cover. Install the mounting nut on the stud. Tighten
stud to 41 N´m (30 ft. lbs.).
(3) Install drive belt (Refer to 7 - COOLING/AC-
CESSORY DRIVE/DRIVE BELTS - INSTALLA-
TION).
(4) Check belt indexing marks (Refer to 7 - COOL-
ING/ACCESSORY DRIVE/DRIVE BELTS - INSTAL-
LATION).
Fig. 1 ACCESSORY DRIVE BRACKET
1- UPPER TIMING BELT COVER
2- LOWER TIMING BELT COVER
3- BELT TENSIONER
4- ACCESSORY DRIVE BRACKET
7s - 14 ACCESSORY DRIVEKJ

ENGINE COOLANT
TEMPERATURE SENSOR
DESCRIPTION
The Engine Coolant Temperature (ECT) sensor is
used to sense engine coolant temperature. The sensor
protrudes into an engine water jacket.
The ECT sensor is a two-wire Negative Thermal
Coefficient (NTC) sensor. Meaning, as engine coolant
temperature increases, resistance (voltage) in the
sensor decreases. As temperature decreases, resis-
tance (voltage) in the sensor increases.
OPERATION
At key-on, the Powertrain Control Module (PCM)
sends out a regulated 5 volt signal to the ECT sensor.
The PCM then monitors the signal as it passes
through the ECT sensor to the sensor ground (sensor
return).
When the engine is cold, the PCM will operate in
Open Loop cycle. It will demand slightly richer air-
fuel mixtures and higher idle speeds. This is done
until normal operating temperatures are reached.
The PCM uses inputs from the ECT sensor for the
following calculations:
²for engine coolant temperature gauge operation
through CCD or PCI (J1850) communications
²Injector pulse-width²Spark-advance curves
²ASD relay shut-down times
²Idle Air Control (IAC) motor key-on steps
²Pulse-width prime-shot during cranking
²O2 sensor closed loop times
²Purge solenoid on/off times
²EGR solenoid on/off times (if equipped)
²Leak Detection Pump operation (if equipped)
²Radiator fan relay on/off times (if equipped)
²Target idle speed
REMOVAL
2.4L
The Engine Coolant Temperature (ECT) sensor is
installed into a water jacket at left front of cylinder
head (Fig. 2).
WARNING: HOT, PRESSURIZED COOLANT CAN
CAUSE INJURY BY SCALDING. COOLING SYSTEM
MUST BE PARTIALLY DRAINED BEFORE REMOV-
ING THE COOLANT TEMPERATURE SENSOR.
(1) Partially drain cooling system.
(2) Disconnect electrical connector from sensor.
(3) Remove sensor from cylinder head.
3.7L
The Engine Coolant Temperature (ECT) sensor is
installed into a water jacket at front of intake mani-
fold near rear of generator (Fig. 3).
Fig. 1 ENGINE BLOCK HEATER 2.4L
1 - CORE HOLE
2 - BLOCK HEATER
3 - POWER CORD
Fig. 2 ECT AND UPPER TIMING BELT COVER/
BOLTS-2.4L
1 - UPPER TIMING BELT COVER
2 - ELECTRICAL CONNECTOR (ECT)
3 - MOUNTING BOLTS (3)
KJENGINE7s-21
ENGINE BLOCK HEATER - 2.4L (Continued)