2002 JEEP LIBERTY 2.4

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

DRIVE BELTS -2.4L
DIAGNOSIS AND TESTING - SERPENTINE
DRIVE BELT DIAGNOSIS
When diagnosing serpentine drive belts, small
cracks that run across ribbed surface of belt from rib
to rib (Fig. 2), are considered normal. These are not a
reason to replace belt. However, cracks running along
a rib (not across) arenotnormal. Any belt with
cracks running along a rib must be replaced (Fig. 2).
Also replace belt if it has excessive wear, frayed cords
or severe glazing.
Refer to SERPENTINE DRIVE BELT DIAGNOSIS
CHART for further belt diagnosis.
SERPENTINE DRIVE BELT DIAGNOSIS CHART
CONDITION POSSIBLE CAUSES CORRECTION
RIB CHUNKING (ONE OR MORE
RIBS HAS SEPARATED FROM
BELT BODY)1. Foreign objects imbedded in
pulley grooves.1. Remove foreign objects from
pulley grooves. Replace belt.
2. Installation damage. 2. Replace belt.
RIB OR BELT WEAR 1. Pulley(s) misaligned. 1. Align pulley(s).
2. Abrasive environment. 2. Clean pulley(s). Replace belt if
necessary.
3. Rusted pulley(s). 3. Clean rust from pulley(s).
4. Sharp or jagged pulley groove
tips.4. Replace pulley.
5. Rubber deteriorated. 5. Replace belt.
LONGITUDINAL BELT CRACKING
(CRACKS BETWEEN TWO RIBS)1. Belt has mistracked from pulley
groove.1. Replace belt.
2. Pulley groove tip has worn away
rubber to tensile member.2. Replace belt.
Fig. 2 Serpentine Accessory Drive Belt Wear
Patterns
1 - NORMAL CRACKS BELT OK
2 - NOT NORMAL CRACKS REPLACE BELT
KJACCESSORY DRIVE7s-15

CONDITION POSSIBLE CAUSES CORRECTION
BELT SLIPS 1. Belt slipping because of
insufficient tension.1. Replace automatic belt tensioner.
2. Belt routed 2. Verify belt routing.
incorrectly
3. Incorrect belt. 3. Replace belt.
4. Belt or pulley subjected to
substance (belt dressing, oil
ethylene glycol) that has reduced
friction.4. Replace belt and clean pulleys.
5. Driven component bearing failure. 5. Replace faulty component
bearing.
6. Belt glazed and hardened from
heat and excessive slippage.6. Replace belt.
ªGROOVE JUMPING9(BELT
DOES NOT MAINTAIN CORRECT
POSITION ON PULLEY)1. Belt tension either too high or too
low.1. Replace automatic belt tensioner.
2. Belt routed 2. Verify belt routing.
incorrectly.
3. Incorrect belt. 3. Replace belt.
4. Pulley(s) not within design
tolerance.4. Replace pulley(s).
5. Foreign object(s) in grooves. 5. Remove foreign objects from
grooves.
6. Pulley misalignment. 6. Check and replace.
7. Belt cord line is broken. 7. Replace belt.
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.
REMOVAL - 2.4L 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.CAUTION: DO NOT LET TENSIONER ARM SNAP
BACK TO THE FREEARM POSITION, SEVERE DAM-
AGE MAY OCCUR TO THE TENSIONER.
Belt tension is not adjustable. Belt adjustment is
maintained by an automatic ( spring load ) belt ten-
sioner.
(1) Disconnect negative battery cable from battery.
(2) Rotate belt tensioner until it contacts its stop.
Remove belt, then slowly rotate the tensioner into
the freearm position.
7s - 16 ACCESSORY DRIVEKJ
DRIVE BELTS -2.4L (Continued)

INSTALLATION - 2.4L 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.
Belt tension is not adjustable. Belt adjustment is
maintained by an automatic ( spring load ) belt ten-
sioner.
(1) Check condition of all pulleys.
CAUTION: When installing the 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.
(2) Install new belt (Fig. 3) or (Fig. 4). Route the
belt around all pulleys except the idler pulley. Rotate
the tensioner arm until it contacts its stop position.
Route the belt around the idler and slowly let the
tensioner rotate into the belt. Make sure the belt is
seated onto all pulleys.
(3) With the drive belt installed, inspect the belt
wear indicator. On 2.4L Engines the gap between the
tang and the housing stop ( measurement A ) must
not exceed 24 mm (.94 inches).
Fig. 3 BELT ROUTING 2.4L WITH A/C
1 - IDLER PULLEY
2 - GENERATOR PULLEY
3 - IDLER PULLEY
4 - POWER STEERING PUMP PULLEY
5 -CRANKSHAFT PULLEY
6 - TENSIONER
7 - A/C COMPRESSOR PULLEY
8 - ACCESSORY DRIVE BELT
Fig. 4 BELT ROUTING 2.4L WITHOUT A/C
1 - IDLER PULLEY
2 - GENERATOR PULLEY
3 - IDLER PULLEY
4 - POWER STEERING PUMP PULLEY
5 -CRANKSHAFT PULLEY
6 - TENSIONER
7 - NON A/C IDLER PULLEY
8 - ACCESSORY DRIVE BELT
KJACCESSORY DRIVE7s-17
DRIVE BELTS -2.4L (Continued)

ENGINE
TABLE OF CONTENTS
page page
COOLANT
DESCRIPTION
DESCRIPTION - HOAT COOLANT.........18
DESCRIPTION - ENGINE COOLANT.......19
OPERATION...........................20
COOLANT RECOVERY PRESS CONTAINER
DESCRIPTION.........................20
OPERATION...........................20
ENGINE BLOCK HEATER - 2.4L
DESCRIPTION.........................20
OPERATION...........................20
REMOVAL - 2.4L........................20
INSTALLATION - 2.4L....................20
ENGINE COOLANT TEMPERATURE SENSOR
DESCRIPTION.........................21
OPERATION...........................21
REMOVAL.............................21
INSTALLATION.........................22
ENGINE COOLANT THERMOSTAT
REMOVAL - 2.4L ENGINE.................22
INSTALLATION - 2.4L ENGINE.............22
RADIATOR
DESCRIPTION.........................22REMOVAL.............................22
CLEANING............................24
INSPECTION..........................24
INSTALLATION.........................24
RADIATOR PRESSURE CAP
DESCRIPTION.........................25
OPERATION...........................25
DIAGNOSIS AND TESTING - RADIATOR
PRESSURE CAP......................25
CLEANING............................25
INSPECTION..........................25
RADIATOR FAN - ELECTRIC
DESCRIPTION.........................26
OPERATION...........................26
REMOVAL.............................26
INSTALLATION.........................27
WATER PUMP - 2.4L
DESCRIPTION.........................27
OPERATION...........................27
REMOVAL - 2.4L ENGINE.................27
INSPECTION..........................28
INSTALLATION - 2.4L ENGINE.............28
COOLANT
DESCRIPTION
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 WHENENGINE 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 equivalent ethylene
glycol base coolant with organic corrosion inhibitors
(called HOAT, for Hybrid Organic Additive Technology)
is recommended. This coolant offers the best engine
cooling without corrosion when mixed with 50% Eth-
ylene Glycol and 50% distilled water to obtain a freeze
point of -37ÉC (-35ÉF). If it loses color or becomes con-
taminated, drain, flush, and replace with fresh prop-
erly mixed coolant solution.
7s - 18 ENGINEKJ

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.
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 coolant prevents water
present in the cooling system from freezing within
temperatures indicated by mixture ratio of coolant to
water.
COOLANT RECOVERY PRESS
CONTAINER
DESCRIPTION
This system works along with the radiator pres-
sure 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/ad-
justing coolant level at atmospheric pressure. This is
done without removing the radiator pressure cap.
²Some reserve coolant to 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.
The coolant reservoir/overflow system has a radia-
tor mounted pressurized cap, an overflow tube, and a
plastic coolant reservoir/overflow tank, mounted to
the right side of the cowl. It is mounted to the cowl
with two nuts on top, and a slide bracket on the bot-
tom.
OPERATION
The pressure chamber keeps the coolant free of
trapped air, provides a volume for expansion and con-
traction, and provides a convenient and safe method
for checking and adjusting coolant level at atmo-
spheric pressure. It also provides some reserve cool-
ant to cover minor leaks, evaporation or boiling
losses. The overflow chamber allows coolant recovery
in case of an overheat.
ENGINE BLOCK HEATER - 2.4L
DESCRIPTION
The block heater is operated by ordinary house
current (110 Volt A.C.) through a power cord and con-
nector located in the engine compartment. The
heater is mounted in a core hole (in place of a core
hole plug) in the engine block, with the heating ele-
ment immersed in coolant.
CAUTION: The power cord must be secured in its
retainer clips, and not positioned so it could con-
tact linkages or exhaust manifolds and become
damaged.
OPERATION
The block heater element is submerged in the cool-
ing system's coolant. When electrical power (110 volt
A.C.) is applied to the element, it creates heat. This
heat is transferred to the engine coolant. This pro-
vides easier engine starting and faster warm-up
when vehicle is operated in areas having extremely
low temperatures.
REMOVAL - 2.4L
(1) Drain cooling system (Refer to 7 - COOLING/
ENGINE - STANDARD PROCEDURE).
(2) Raise vehicle on hoist.
(3) Detach power cord plug from heater.
(4) Loosen screw in center of heater. Remove
heater assembly.
INSTALLATION - 2.4L
(1) Thoroughly clean core hole and heater seat.
(2) Insert heater assembly (Fig. 1) with element
loop positionedupward.
(3) With heater seated, tighten center screw
securely to assure a positive seal.
CAUTION: To prevent damage, the power cord must
be secured in it's retaining clips, and not positioned
so it could contact linkages or exhaust manifold.
(4) Connect power cord to heater.
(5) Lower vehicle.
(6) Fill cooling system (Refer to 7 - COOLING/EN-
GINE - STANDARD PROCEDURE).
7s - 20 ENGINEKJ
COOLANT (Continued)

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)

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.
INSTALLATION
(1) Apply thread sealant to sensor threads.
(2) Install sensor to engine.
(3) Tighten sensor to 11 N´m (8 ft. lbs.) torque.
(4) Replace any lost engine coolant.
ENGINE COOLANT
THERMOSTAT
REMOVAL - 2.4L ENGINE
(1) Drain cooling system below the thermostat
level.
(2) Remove radiator upper hose from the coolant
outlet housing.
(3) Remove coolant outlet housing bolts and hous-
ing.
(4) Remove thermostat. Discard gasket and clean
both gasket sealing surfaces.
INSTALLATION - 2.4L ENGINE
(1) Place a new gasket (dipped in clean water) on
the coolant outlet connector surface. Position thermo-
stat with air bleed at the 12 o'clock position in ther-
mostat housing.
(2) Position the coolant outlet connector and gas-
ket over the thermostat, making sure thermostat is
seated in the thermostat housing.
(3) Position outlet connector to thermostat housing
and install bolts. Tighten bolts to 28 N´m (250 in.
lbs.).
(4) Install the radiator upper hose to coolant outlet
housing.
(5) Refill the cooling system.
RADIATOR
DESCRIPTION
All vehicles are equipped with a cross flow type
radiator with plastic side tanks (Fig. 4).
Plastic tanks, while stronger than brass, are sub-
ject to damage by impact, such as from tools or
wrenches. Handle radiator with care.
REMOVAL
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. REFER TO COOLING SYSTEM DRAIN-
ING.
Fig. 3 MAP SENSOR / ECT SENSOR - 3.7L
1 - MOUNTING SCREWS
2 - MAP SENSOR
3 - ECT SENSOR
Fig. 4 Cross Flow Radiator - Typical
1 - RADIATOR
7s - 22 ENGINEKJ
ENGINE COOLANT TEMPERATURE SENSOR (Continued)