(6) Fill cooling system. (Refer to 7 - COOLING -
STANDARD PROCEDURE)
ENGINE COOLANT
THERMOSTAT
DESCRIPTION
The engine cooling thermostats are a wax pellet
driven, reverse poppet choke type. The thermostat is
mounted in a housing on the coolant outlet of the
engine (Fig. 8) or (Fig. 10).
OPERATION
The engine cooling thermostat is a wax pellet
driven, reverse poppet choke type. The thermostat is
designed to provide the fastest warm up possible by
preventing leakage through it and to guarantee a
minimum engine operating temperature of 88 to
93ÉC (192 to 199ÉF). The thermostat also will auto-
matically reach wide open so it will not restrict flow
to the radiator as temperature of the coolant rises in
hot weather to around 104ÉC (220ÉF). Above this
temperature the coolant temperature is controlled by
the radiator, fan, and ambient temperature, not the
thermostat.
The thermostat is operated by a wax filled con-
tainer (pellet) which is sealed. When heated coolantreaches a predetermined temperature, the wax
expands enough to overcome the closing spring and
water pump pressure, which forces the valve to open.
DIAGNOSIS AND TESTING - ENGINE COOLANT
THERMOSTAT
The thermostat is operated by a wax filled cham-
ber (pellet) which is sealed. When heated coolant
reaches a predetermined temperature the wax pellet
expands enough to overcome the closing spring and
water pump pressure, which forces the valve to open.
Coolant leakage into the pellet will cause a thermo-
stat to fail open. Do not attempt to free up a thermo-
stat with a screwdriver.
Thermostat diagnostics is included in powertrain
control module's (PCM) programing for on-board
diagnosis. The malfunction indicator light (MIL) will
illuminate and a diagnostic trouble code (DTC) will
be set when an ªopen too soonº condition occurs. Do
not change a thermostat for lack of heater perfor-
mance or temperature gauge position, unless a DTC
is present. For other probable causes, (Refer to 7 -
COOLING/ENGINE - DIAGNOSIS AND TESTING).
Thermostat failing shut is the normal long term
mode of failure, and normally, only on high mileage
vehicles. The temperature gauge will indicate this
(Refer to 7 - COOLING/ENGINE - DIAGNOSIS AND
TESTING).
ENGINE COOLANT
THERMOSTAT - 2.4L
REMOVAL
(1) Drain cooling system below the thermostat
level. (Refer to 7 - COOLING - STANDARD PROCE-
DURE)
(2) Remove radiator upper hose from the coolant
outlet housing (Fig. 7).
(3) Remove coolant outlet housing bolts and hous-
ing (Fig. 8).
(4) Remove thermostat. Discard gasket and clean
both gasket sealing surfaces.
INSTALLATION
(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 (Fig. 8).
(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 (Fig. 8). Tighten bolts to 28 N´m
(250 in. lbs.).
Fig. 6 Engine Coolant Temperature Sensor
1 - ENGINE COOLANT TEMPERATURE SENSOR
2 - CONNECTOR - ENGINE COOLANT SENSOR
3 - FITTING - HEATER SUPPLY
RSENGINE7-23
ENGINE COOLANT TEMPERATURE SENSOR - 3.3/3.8L (Continued)
ProCarManuals.com
(4) Install the radiator upper hose to coolant outlet
housing (Fig. 7).
(5) Refill the cooling system. (Refer to 7 - COOL-
ING - STANDARD PROCEDURE)
ENGINE COOLANT
THERMOSTAT - 3.3/3.8L
REMOVAL
(1) Drain cooling system down below the thermo-
stat level. (Refer to 7 - COOLING - STANDARD
PROCEDURE)
(2) Remove radiator upper hose from coolant outlet
connector (Fig. 9).
(3) Remove coolant outlet connector bolts and con-
nector (Fig. 10).
(4) Remove thermostat from outlet connector.
(5) Discard gasket and clean both gasket sealing
surfaces.
INSTALLATION
(1) To ensure proper seating of replacement ther-
mostat, carefully remove the bulged metal from the
wall of the outlet connector recess that was created
during the staking procedure that held the OEM
thermostat in place (Fig. 11). It is not necessary to
restake the replacement thermostat into the connec-
tor.
(2) Position thermostat to coolant outlet connector.
Align the two locating notches on thermostat to the
connector (Fig. 12). This position will ensure proper
location of the thermostat air bleed.
Fig. 7 RADIATOR HOSES TO ENGINE - 2.4L
1 - UPPER HOSE
2 - LOWER HOSE
Fig. 8 Thermostat and Outlet Connector - 2.4L
Engine
1 - THERMOSTAT
2 - GASKET
3 - COOLANT OUTLET CONNECTOR
4 - BOLT
Fig. 9 RADIATOR HOSES TO ENGINE - 3.3/3.8L
1 - UPPER HOSE
2 - LOWER HOSE
7 - 24 ENGINERS
ENGINE COOLANT THERMOSTAT - 2.4L (Continued)
ProCarManuals.com
(3) Position a new gasket over the thermostat and
connector making sure thermostat is in proper posi-
tion and in the recess provided.
(4) Install thermostat and connector assembly to
the intake manifold (Fig. 10). Tighten bolts to 28
N´m (250 in. lbs.).
(5) Install the radiator upper hose to coolant outlet
connector (Fig. 9).
(6) Refill the cooling system to the proper level.
(Refer to 7 - COOLING - STANDARD PROCEDURE)
RADIATOR
DESCRIPTION
The radiator is a cross-flow type (horizontal tubes)
with design features that provide greater strength
along with sufficient heat transfer capabilities to
keep the engine satisfactorily cooled. The radiator
has plastic side tanks and aluminum cooling tubes.
OPERATION
The radiator functions as a heat exchanger, using
air flow across the exterior of the radiator tubes. This
heat is then transferred from the coolant and into
the passing air.
REMOVAL
(1) Disconnect negative cable from battery.
(2) Remove radiator upper crossmember support.
(Refer to 23 - BODY/EXTERIOR/GRILLE OPENING
REINFORCEMENT - REMOVAL)
WARNING: DO NOT REMOVE THE CYLINDER
BLOCK PLUG OR THE RADIATOR DRAINCOCK
WITH THE SYSTEM HOT AND UNDER PRESSURE
BECAUSE SERIOUS BURNS FROM COOLANT CAN
OCCUR.
(3) Drain the cooling system. (Refer to 7 - COOL-
ING - STANDARD PROCEDURE)
(4) Remove the radiator fans. (Refer to 7 - COOL-
ING/ENGINE/RADIATOR FAN - REMOVAL)
(5) Disconnect coolant reserve/recovery hose.
Fig. 10 THERMOSTAT - 3.3/3.8L ENGINE
1 - COOLANT OUTLET CONNECTOR
2 - BOLT
3 - THERMOSTAT
4 - GASKET
Fig. 11 Connector Staking Material Removal
1-STAKE
2 - OUTLET CONNECTOR
Fig. 12 Thermostat Position In Outlet Connector
1 - LOCATING NOTCH
2 - THERMOSTAT
3 - COOLANT OUTLET CONNECTOR
RSENGINE7-25
ENGINE COOLANT THERMOSTAT - 3.3/3.8L (Continued)
ProCarManuals.com
WATER PUMP - 2.4L
DESCRIPTION
The water pump has a cast aluminum body and
housing with a stamped steel impeller. The water
pump bolts directly to the block (Fig. 23). The cylin-
der block to water pump seal is provided by a rubber
O-ring. The water pump is driven by the engine tim-
ing belt.
OPERATION
The water pump is the heart of the cooling system.
The coolant is pumped through the engine block, cyl-
inder head, heater core, and radiator.
REMOVAL
(1) Disconnect negative cable from battery.
(2) Raise vehicle on a hoist.
(3) Remove the right inner splash shield.
(4) Remove the accessory drive belts (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(5) Drain the cooling system (Refer to 7 - COOL-
ING - STANDARD PROCEDURE).
(6) Support engine from the bottom and remove
right engine mount. (Refer to 9 - ENGINE/ENGINE
MOUNTING/RIGHT MOUNT - REMOVAL).(7) Remove right engine mount bracket (Fig. 24).
(8) Remove the timing belt (Refer to 9 - ENGINE/
VALVE TIMING/TIMING BELT AND SPROCKET(S)
- REMOVAL).
(9) Remove timing belt idler pulley.
(10) Hold camshaft sprocket with Special tool
C-4687 and adaptor C-4687-1 while removing bolt.
Remove both cam sprockets.
(11) Remove the timing belt rear cover (Refer to 9
- ENGINE/VALVE TIMING/TIMING BELT COV-
ER(S) - REMOVAL).
(12) Remove the generator and bracket (Fig. 24).
(13) Remove water pump to engine attaching
screws (Fig. 25).
CLEANING
Clean gasket mating surfaces as necessary.
INSPECTION
Replace water pump body assembly if it has any of
these defects:
(1) Cracks or damage on the body.
(2) Coolant leaks from the shaft seal, evident by
wet coolant traces on the pump body.
(3) Loose or rough turning bearing.
(4) Impeller rubs either the pump body or the
engine block.
(5) Impeller loose or damaged.
(6) Sprocket or sprocket flange loose or damaged.
INSTALLATION
(1) Install new O-ring gasket in water pump body
O-ring locating groove (Fig. 26).
CAUTION: Make sure O-ring is properly seated in
water pump groove before tightening screws. An
improperly located O-ring may be damaged and
cause a coolant leak.
(2) Assemble pump body to block and tighten
screws to 12 N´m (105 in. lbs.) (Fig. 25). Pressurize
cooling system to 103.4 Kpa (15 psi) with pressure
tester and check water pump shaft seal and O-ring
for leaks.
(3) Rotate pump by hand to check for freedom of
movement.
(4) Install the timing belt rear cover (Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT COVER(S)
- INSTALLATION).
(5) Install camshaft sprockets and torque bolts to
101 N´m (75 ft. lbs.) while holding camshaft sprocket
with Special tool C-4687 and adaptor C-4687-1.
(6) Install timing belt idler pulley and torque
mounting bolt to 61 N´m (45 ft. lbs.).
Fig. 23 Water Pump
1 - CYLINDER BLOCK
2 - WATER PUMP
7 - 32 ENGINERS
ProCarManuals.com
(7) Install the timing belt (Refer to 9 - ENGINE/
VALVE TIMING/TIMING BELT AND SPROCKET(S)
- INSTALLATION).
(8) Install the generator mount bracket. (Fig. 24)
(9) Install the generator.
(10) Install right engine mount bracket and engine
mount (Refer to 9 - ENGINE/ENGINE MOUNTING/
RIGHT MOUNT - INSTALLATION).
(11) Fill the cooling system (Refer to 7 - COOLING
- STANDARD PROCEDURE).
(12) Install the accessory drive belts (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
INSTALLATION).
(13) Lower vehicle and connect battery cable.
WATER PUMP - 3.3/3.8L
DESCRIPTION
The water pump has a die-cast aluminum body
and a plastic impeller. It bolts directly to the timing
chain case cover, using a rubber seal for sealing (Fig.
27). It is driven by the accessory drive belt.
OPERATION
The water pump is the heart of the cooling system.
The coolant is pumped through the engine block, cyl-
inder head, heater core, and radiator.
REMOVAL
(1) Drain the cooling system. (Refer to 7 - COOL-
ING - STANDARD PROCEDURE)
(2) Remove the accessory drive belt shield.
(3) Remove the accessory drive belt. (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL)
(4) Remove water pump pulley bolts (Fig. 27).
NOTE: To remove the water pump pulley, it MUST
first be positioned between water pump housing
and drive hub. The pulley can then be removed with
the water pump assembly.
(5) Rotate pulley until openings in pulley align
with water pump drive hub spokes (Fig. 28). Move
pulley inward between pump housing and hub (Fig.
28).
(6) Position pulley to allow access to water pump
mounting bolts. Remove water pump mounting bolts
(Fig. 29).
(7) Remove water pump with the pulley loosely
positioned between hub and the pump body.
(8) Remove and discard the seal.
Fig. 27 Water Pump - 3.3/3.8L Engine
1 - WATER PUMP
2 - PULLEY - WATER PUMP
3 - BOLT - PULLEY
4 - BOLT - WATER PUMP
5 - SEAL - WATER PUMP
Fig. 28 Water Pump Pulley Positioning
1 - HUB - WATER PUMP
2 - PULLEY - WATER PUMP
7 - 34 ENGINERS
WATER PUMP - 2.4L (Continued)
ProCarManuals.com
(5) Rotate pump by hand to check for freedom of
movement.
(6) Install the accessory drive belt. (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
INSTALLATION)
(7) Install drive belt shield.
(8) Fill the cooling system. (Refer to 7 - COOLING
- STANDARD PROCEDURE)
WATER PUMP INLET TUBE -
2.4L
DESCRIPTION
The 2.4L engine uses a metal tube to connect the
engine block to the lower radiator hose and heater
return (Fig. 32). The tube has an O-ring for block to
tube sealing and bolts attach the tube to the engine
block.
REMOVAL
(1) Drain the cooling system. (Refer to 7 - COOL-
ING - STANDARD PROCEDURE)
(2) Remove radiator upper hose to access the hose
connections at the inlet tube.
(3) Remove radiator lower (Fig. 7) and heater
hoses from the inlet tube (Fig. 33).
(4) Remove the two fasteners that hold the inlet
tube to the block.
(5) Rotate tube while removing the tube from the
engine block.
INSTALLATION
(1) Inspect the O-ring for damage before installing
the tube into the cylinder block (Fig. 32).(2) Lube O-ring with coolant and install inlet tube
into the cylinder block opening (Fig. 32).
(3) Install the two inlet tube fasteners and tighten
to 12 N´m (105 in. lbs.).
(4) Connect the radiator lower hose (Fig. 7) and
heater hose to inlet tube (Fig. 33).
(5) Install the radiator upper hose.
(6) Fill the cooling system. (Refer to 7 - COOLING
- STANDARD PROCEDURE)
WATER PUMP INLET TUBE -
3.3/3.8L
REMOVAL
(1) Drain the cooling system. (Refer to 7 - COOL-
ING - STANDARD PROCEDURE)
(2) Raise vehicle on hoist and remove the belt
splash shield.
(3) Remove the radiator lower hose from inlet tube
(Fig. 34).
(4) Remove the oil cooler outlet/heater return hose
from inlet tube (only if equipped with engine oil
cooler) (Fig. 35).
(5) Remove the inlet tube bolts (Fig. 36).
(6) Remove the inlet tube (Fig. 36). Discard the
O-ring seal.
INSTALLATION
(1) Clean the inlet tube O-ring sealing surfaces on
the timing cover housing and tube.
(2) Apply MopartDielectric Grease or equivalent
to the O-ring before installation.
(3) Position new O-ring seal on inlet tube (Fig. 36).
Fig. 32 Water Pump Inlet TubeÐ2.4L Engine
1 - O-RING
2 - WATER PUMP INLET TUBE
Fig. 33 Water Pump Inlet Tube Hose Connections
1 - WATER PUMP INLET TUBE
2 - HOSE - HEATER RETURN
3 - COOLANT INLET
7 - 36 ENGINERS
WATER PUMP - 3.3/3.8L (Continued)
ProCarManuals.com
ENGINE COOLANT
THERMOSTAT
DESCRIPTION
A pellet-type thermostat controls the operating
temperature of the engine by controlling the amount
of coolant flow to the radiator (Fig. 9).
OPERATION
The thermostat starts to open at 80ÉC (176ÉF).
Above this temperature, coolant is allowed to flow to
the radiator. This provides quicker engine warmup
and overall temperature control.
The same thermostat is used for winter and sum-
mer seasons. An engine should not be operated with-
out a thermostat, except for servicing or testing.
Operating without a thermostat causes other prob-
lems. These are: longer engine warmup time, unreli-
able warmup performance, increased exhaust
emissions and crankcase condensation. This conden-
sation can result in sludge formation.
REMOVAL
NOTE: The thermostat is not serviced separately.
The thermostat and housing must be replaced as
an assembly.
(1) Disconnect negative battery cable.
(2) Drain cooling system (Refer to 7 - COOLING/
ENGINE/COOLANT - STANDARD PROCEDURE).
(3) Remove front wiper unit to gain access to ther-
mostat housing(Refer to 8 - ELECTRICAL/WIPERS/
WASHERS/WIPER MODULE - REMOVAL).
(4) Disconnect upper radiator hose adapter tube,
water pump hose, and EGR hose at thermostat hous-
ing.
(5) Remove both thermostat housing attaching
bolts and housing (Fig. 10).
INSTALLATION
(1) Install thermostat housing, gasket, and retain-
ing bolts (Fig. 10). Torque bolts to 27.5N´m.
(2) Connect upper radiator hose adapter tube,
water pump hose, and EGR cooler hose to thermostat
housing.
Fig. 8 COOLANT TEMPERATURE SENSOR
LOCATION
1 - EGR SOLENOID
2 - UPPER RADIATOR HOSE
3 - COOLANT TEMPERATURE SENSOR
4 - INTAKE MANIFOLD INLET
5 - INTAKE MANIFOLD/CYLINDER HEAD COVER
Fig. 9 THERMOSTAT HOUSING LOCATION
1 - CYLINDER HEAD COVER
2 - THERMOSTAT HOUSING
3 - AIR BLEED
4 - WATER PUMP
5 - WATER PUMP HOUSING TO THERMOSTAT HOUSING
BYPASS HOSE
6 - E G R VA LV E
7a - 20 ENGINERG
ENGINE COOLANT THERMOSTAT (Continued)
ProCarManuals.com
(3) Install front wiper unit (Refer to 8 - ELECTRI-
CAL/WIPERS/WASHERS/WIPER MODULE -
INSTALLATION).
(4) Refill cooling system (Refer to 7 - COOLING/
ENGINE/COOLANT - STANDARD PROCEDURE).
(5) Connect negative battery cable.
RADIATOR
DESCRIPTION
The radiator is a cross-flow type (horizontal tubes)
with design features that provide greater strength
along with sufficient heat transfer capabilities to
keep the engine satisfactorily cooled. The radiator
has plastic side tanks and aluminum cooling tubes.
OPERATION
The radiator functions as a heat exchanger, using
air flow across the exterior of the radiator tubes. This
heat is then transferred from the coolant and into
the passing air.
REMOVAL
(1) Disconnect negative cable from battery.
(2) Remove radiator upper crossmember support.
(Refer to 23 - BODY/EXTERIOR/GRILLE OPENING
REINFORCEMENT - REMOVAL)
WARNING: DO NOT REMOVE THE CYLINDER
BLOCK PLUG OR THE RADIATOR DRAINCOCK
WITH THE SYSTEM HOT AND UNDER PRESSURE
BECAUSE SERIOUS BURNS FROM COOLANT CAN
OCCUR.
(3) Drain the cooling system (Refer to 7 - COOL-
ING/ENGINE/COOLANT - STANDARD PROCE-
DURE).
(4) Remove the radiator fans. (Refer to 7 - COOL-
ING/ENGINE/RADIATOR FAN - REMOVAL)
(5) Disconnect coolant bypass hose (Fig. 11).
(6) Disconnect upper and lower hoses from the
radiator (Fig. 11).
(7) Remove the A/C condenser side brackets to
radiator attaching screws (Fig. 12). Separate the con-
denser from the radiator by lifting upward to disen-
gage from lower mounts (Fig. 12). Allow the
condenser to rest in front of radiator.
Fig. 10 THERMOSTAT HOUSING ASSEMBLY
1 - THERMOSTAT HOUSING GASKET
2 - THERMOSTAT HOUSING
3 - RETAINING BOLTS
4 - CYLINDER HEAD
5 - CYLINDER HEAD COVER/INTAKE MANIFOLD
Fig. 11 UPPER AND LOWER RADIATOR HOSES
1 - COOLANT BYPASS HOSE
2 - RADIATOR ASSEMBLY
3 - UPPER RADIATOR HOSE
4 - COOLING FAN
5 - LOWER RADIATOR HOSE
6 - CHARGE AIR COOLER
7 - RADIATOR BRACKET
RGENGINE7a-21
ENGINE COOLANT THERMOSTAT (Continued)
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