With engine not running, remove radiator pressure
cap and wipe the radiator filler neck sealing seat
clean. The radiator should be full.
Attach the Cooling System Tester 7700 or equiva-
lent to the radiator, as shown in (Fig. 4) and apply
104 kPa (15 psi) pressure. If the pressure drops more
than 13.8 kPa (2 psi) in 2 minutes, inspect all points
for external leaks.
All radiator and heater hoses should be shaken
while at 104 kPa (15 psi), since some leaks occur only
while driving due to engine movement.If there are no external leaks, after the gauge dial
shows a drop in pressure, detach the tester. Start
engine and run until the thermostat opens, allowing
the coolant to expand. Reattach the cooling system
tester. If the needle on the dial fluctuates it indicates
a combustion leak, usually a head gasket leak.
WARNING: WITH TOOL IN PLACE, PRESSURE WILL
BUILD UP FAST. EXCESSIVE PRESSURE BUILT UP,
BY CONTINUOUS ENGINE OPERATION, MUST BE
RELEASED TO A SAFE PRESSURE POINT. NEVER
PERMIT PRESSURE TO EXCEED 138 kPa (20 psi).
If the needle on the dial does not fluctuate, raise
the engine rpm a few times. If an abnormal amount
of coolant or steam emits from the tailpipe, it may
indicate a coolant leak caused by a faulty head gas-
ket, cracked engine block, or cracked cylinder head.
There may be internal leaks that can be deter-
mined by removing the oil dipstick. If water globules
appear intermixed with the oil it will indicate an
internal leak in the engine. If there is an internal
leak, the engine must be disassembled for repair.
DIAGNOSIS AND TESTING - COOLING SYSTEM
FLOW CHECK
To determine whether coolant is flowing through
the cooling system, use one of the following proce-
dures:
PREFERRED METHOD
WARNING: DO NOT REMOVE THE COOLING SYS-
TEM PRESSURE CAP OR ANY HOSE WITH THE
SYSTEM HOT AND UNDER PRESSURE BECAUSE
SERIOUS BURNS FROM COOLANT CAN OCCUR.
²Remove pressure cap when engine is cold.
Remove small amount of coolant. Idle engine until
thermostat opens. You should observe coolant flow
while looking down the filler neck. Once flow is
detected install the pressure cap. Replace removed
coolant into coolant recovery container.
ALTERNATIVE METHOD
²If engine is cold, idle engine until normal oper-
ating temperature is reached. Feel the upper radiator
hose. If it is hot, coolant is circulating.
Fig. 3 Hose Clamp Tool
1 - HOSE CLAMP TOOL 6094
2 - HOSE CLAMP
Fig. 4 Pressure Testing
RSCOOLING7-3
COOLING (Continued)
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ENGINE
DIAGNOSIS AND TESTING - ENGINE COOLING
SYSTEM
Establish what driving condition caused the cooling
system complaint. The problem may be caused by an
abnormal load on the system such as the following:
prolonged idle, very high ambient temperature, slight
tail wind at idle, slow traffic speed, traffic jam, high
speed, steep grade.
DRIVING TECHNIQUES
To avoid overheating the cooling system:
(1) Idle with A/C off when temperature gauge is at
end of normal range.
(2) Do not increase engine speed for more air flow
and coolant flow because the electric motor fan sys-
tems are not responsive to engine RPM. The added
cooling from higher coolant flow rate is more than
offset by increased heat rejection (engine heat added
to coolant).
TRAILER TOWING
Consult the owner's manual under Trailer Towing
and do not exceed specified limits.
VISUAL INSPECTION
If the cooling system problem is not caused by a
driving condition, perform a visual inspection to
determine if there was a recent service or accident
repair, including the following:
²Loose/damaged water pump drive belt
²Incorrect cooling system refilling (trapped air or
low level)
²Brakes possibly dragging
²Damaged hoses
²Loose/damaged hose clamps
²Damaged/incorrect engine thermostat
²Damaged cooling fan motor, fan blade and fan
shroud
²Damaged head gasket
²Damaged water pump
²Damaged radiator
²Damaged coolant recovery system
²Damaged heater core
²Open/shorted electrical circuits
If the visual inspection reveals none of the above
as cause for a cooling system complaint, refer to the
following diagnostic charts.
COOLING SYSTEM DIAGNOSIS CHART
CONDITION POSSIBLE CAUSES CORRECTION
PRESSURE CAP IS BLOWING
OFF STEAM AND/OR COOLANT.
TEMPERATURE GAUGE READING
MAY BE ABOVE NORMAL BUT
NOT HIGH. COOLANT LEVEL MAY
BE HIGH IN COOLANT RESERVE/
OVERFLOW TANK.1. Pressure relief valve in radiator
cap is defective, or was not
properly seated.1. Check condition of radiator cap
and cap seal. (Refer to 7 -
COOLING/ENGINE/RADIATOR
PRESSURE CAP - DIAGNOSIS
AND TESTING) Replace cap as
necessary.
2. Incorrect cap was installed. 2. Replace cap as necessary.
3. Incorrect coolant mixture. 3. Check concentration level of the
coolant. (Refer to 7 - COOLING/
ENGINE/COOLANT - DIAGNOSIS
AND TESTING) Adjust the ethylene
glycol-to-water ratio as required.
COOLANT LOSS TO THE
GROUND WITHOUT PRESSURE
CAP BLOWOFF. GAUGE IS
READING HIGH OR HOT.1. Coolant leaks in radiator, cooling
system hoses, water pump or
engine.1. Pressure test and repair as
necessary. (Refer to 7 - COOLING -
DIAGNOSIS AND TESTING)
RSENGINE7-15
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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
CONDITION POSSIBLE CAUSES CORRECTION
6. Freeze point of antifreeze not
correct. Mixture may be too rich.6. Check antifreeze. Adjust
antifreeze-to-water ratio as
required.
7. Coolant not flowing through
system.7. Check for coolant flow in
coolant tank with engine warm
and thermostat open. Coolant
should be observed flowing
through the tank. If flow is not
observed, determine reason for
lack of flow and repair as
necessary.
8. Radiator or A/C condensor fins
are dirty or clogged.8. Clean debris from radiator or
A/C condensor
9. Radiator core is corroded or
plugged.9. Have radiator re-cored or
replaced.
10. Aftermarket A/C installed without
proper A/C condensor.10. Install proper A/C
condensor.
11. Dragging Brakes. 11. Check and correct as
necessary.
12. Non-factory bug screen is being
used reducing airflow.12. Only a factory screen
should be used.
13. Thermostat partially or
completely shut. This is more
prevalent on high mileage vehicles.13. Check thermostat and
replace if necessary.
14. Cylinder head gasket leaking. 14. Check cylinder head gasket
for leaks.
15. Heater core leaking. 15. Check heater cor for leaks.
Repair as necessary.
TEMPERATURE GAUGE
READING IS
INCONSISTENT
(FLUCTUATES, CYCLES
OR IS ERRATIC)1. During cold weather operation,
with the heater blower in the high
position, the gauge reading may
drop slightly. Fluctuation is also
influenced by loads, outside
temperature and extended idle time
with diesel engines.1. A normal condition. No
correction is necessary.
2. Temperature gauge or engine
mounted gauge sensor defective or
shorted. Also, corroded or loose
wiring in this circuit.2. Check operation of gauge
and repair as necessary.
3. Gauge reading rises when vehicle
is brought to a stop after heavy use
(engine still running).3. A normal condition. No
correction needed. Gauge
should return to normal range
after vehicle is driven.
4. Gauge reading high after starting
a warm-iup (hot) engine.4. A normal condition. No
correction needed. Gauge
should return to normal after a
few minutes of engine
operation.
RGCOOLING 2.5L TURBO DIESEL7a-3
COOLING 2.5L TURBO DIESEL (Continued)
ProCarManuals.com
CONDITION POSSIBLE CAUSES CORRECTION
5. Coolant level low in the coolant
tank (air will build up in the cooling
system causing the thermostat to
open late).5. Check and correct coolant
leaks.
6. Cylinder head gasket leaking
allowing exhaust gases to enter the
cooling system causing the
thermostat to open late.6. (a) Check for cylinder head
gasket leaks with a
commercially available leak
tester. (b) Check for coolant in
engine oil. Inspect for white
steam emitting from exhaust
system. Repair as necessary.
7. Water pump impeller loose on
shaft.7. Check water pump and
replace as necessary.
8. Loose accessory drive belt (water
pump slipping).8. Check and correct as
necessary.
9. Air leak on the suction side of the
water pump allowing air to build up
in the cooling system causing the
thermostat to open late.9. Locate leak and repair as
necessary.
PRESSURE CAP IS
BLOWING OFF STEAM
AND/OR COOLANT.
TEMPERATURE GAUGE
READING MAY BE ABOVE
NORMAL BUT NOT HIGH.
COOLANT LEVEL MAY BE
HIGH IN COOLANT TANK1. Pressure relief valve in pressure/
vent cap is defective.1. Check condition of
pressure/vent cap and cap
seals.
2. Head gasket leak or cracked
cylinder head.2. Repair as necessary.
COOLANT LOSS TO THE
GROUND WITHOUT
PRESSURE CAP
BLOWOFF. GAUGE IS
READING HIGH OR HOT1. Coolant leaks in radiator, cooling
system hoses, water pump, or
engine.1. Pressure test cooling system
and repair as necessary.
HOSE OR HOSES
COLLAPSE WHEN
ENGINE IS COOLING1. Vacuum created in cooling system
on engine cool-down is not being
relieved through pressure/vent cap.1. Cap relief valve stuck.
Replace if necessary.
NOISY FAN 1. Cooling fan blades loose. 1. Replace cooling fan
assembly.
2. Cooling fan blades striking a
surrounding object.2. Locate point of fan blade
contact and repair as
necessary.
3. Air obstructions at radiator or A/C
condensor.3. Remove obstructions or
clean debris from radiator or
A/C condensor.
7a - 4 COOLING 2.5L TURBO DIESELRG
COOLING 2.5L TURBO DIESEL (Continued)
ProCarManuals.com
CONDITION POSSIBLE CAUSES CORRECTION
4. Has undercoating been applied to
any unnecessary components?4. Clean undercoating as
necessary.
STEAM IS COMING FROM
FRONT OF VEHICLE
NEAR GRILL AREA WHEN
WEATHER IS WET,
ENGINE IS WARMED UP
AND RUNNING, AND
VEHICLE IS STATIONARY.
TEMPERATURE GAUGE
IS IN NORMAL RANGE1. During wet weather, moisture
(snow, ice, or rain condensation) on
the radiator will evaporate when the
thermostat opens. This opening
allows heated water into the radiator.
When the moisture contacts the hot
radiator, steam may be emitted. This
usually occurs in cold weather with
no fan or airflow to blow it away.1. Occasional steam emitting
from this area is normal. No
repair is necessary.
COOLANT ODOR 1. Coolant color is not necessarily an
indication of adequate corrosion or
temperature protection. Do not rely
on coolant color for determining
condition of coolant.1. Refer to Coolant in this group
for antifreeze tests. Adjust
antifreeze-to-water ratio as
necessary.
COOLANT LEVEL
CHANGES IN COOLANT
TANK. TEMPERATURE
GAUGE IS IN NORMAL
RANGE1. Level changes are to be expected
as coolant volume fluctuates with
engine temperature. If the level in
the tank was between the HOT and
COLD marks at normal engine
operating temperature, the level
should return to within that range
after operation at elevated
temperatures.1. This a normal condition. No
repair necessary.
DIAGNOSIS AND TESTING - COOLING SYSTEM
LEAK TEST
WARNING: THE WARNING WORDS ªDO NOT OPEN
HOTº ON THE RADIATOR PRESSURE CAP IS A
SAFETY PRECAUTION. WHEN HOT, PRESSURE
BUILDS UP IN COOLING SYSTEM. TO PREVENT
SCALDING OR INJURY, THE RADIATOR CAP
SHOULD NOT BE REMOVED WHILE THE SYSTEM
IS HOT OR UNDER PRESSURE.
With engine not running, remove pressure/vent cap
from the coolant recovery pressure container and
wipe the filler neck sealing seat clean. The coolant
recovery pressure container should be full.
Attach the Cooling System Tester 7700 or equiva-
lent to the radiator, as shown in (Fig. 1) and apply
104 kPa (15 psi) pressure. If the pressure drops more
than 13.8 kPa (2 psi) in 2 minutes, inspect all points
for external leaks.
All radiator and heater hoses should be shaken
while at 104 kPa (15 psi), since some leaks occur only
while driving due to engine movement.
If there are no external leaks, after the gauge dial
shows a drop in pressure, detach the tester. Startengine and run until the thermostat opens, allowing
the coolant to expand. Reattach the cooling system
tester. If the needle on the dial fluctuates it indicates
a combustion leak, usually a head gasket leak.
WARNING: WITH TOOL IN PLACE, PRESSURE WILL
BUILD UP FAST. EXCESSIVE PRESSURE BUILT UP,
BY CONTINUOUS ENGINE OPERATION, MUST BE
RELEASED TO A SAFE PRESSURE POINT. NEVER
PERMIT PRESSURE TO EXCEED 138 kPa (20 psi).
If the needle on the dial does not fluctuate, raise
the engine rpm a few times. If an abnormal amount
of coolant or steam emits from the tailpipe, it may
indicate a coolant leak caused by a faulty head gas-
ket, cracked engine block, or cracked cylinder head.
There may be internal leaks that can be deter-
mined by removing the oil dipstick. If water globules
appear intermixed with the oil it will indicate an
internal leak in the engine. If there is an internal
leak, the engine must be disassembled for repair.
7a - 6 COOLING 2.5L TURBO DIESELRG
COOLING 2.5L TURBO DIESEL (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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