at running operating temperature the high pressure
inlet tank runs full and the low pressure outlet tank
drops:
²Transmission oil will become hotter.
²High reading shown on the temperature gauge.
²Air in the coolant can cause loss of flow through
the heater.
²Exhaust gas leaks into the coolant also can
cause the same problems.
DEAERATION
Air can only be removed from the system by gath-
ering under the pressure cap. On the next heat up it
will be pushed past the pressure cap into the CRS
tank by thermal expansion of the coolant. It then
escapes to the atmosphere in the CRS tank and is
replaced with solid coolant on cool down.
TEMPERATURE GAUGE INDICATION
At idle with Air Conditioning off the temperature
gauge will rise slowly to about 5/8 gauge travel, the
fan will come on and the gauge will quickly drop to
about 1/2 gauge travel. This is normal.
SERVICE PROCEDURES
COOLANT LEVEL CHECKÐROUTINE
Do not remove radiator cap for routine cool-
ant level inspections.
The coolant reserve system provides a quick visual
method for determining the coolant level without
removing the radiator cap.With the engine cold
and not running,simply observe the level of the
coolant in the reserve tank (Fig. 3). The coolant level
should be between the minimum and maximum
marks.
COOLANTÐADDING ADDITIONAL
The radiator cap should not be removed.
When additional coolant is needed to maintain this
level, it should be added to the coolant reserve tank.
Use only 50/50 mix of ethylene glycol type antifreeze
and water.
CAUTION: Do not use well water, or suspect water
supply in cooling system. A 50/50 ethylene glycol
and distilled water mix is recommended.
COOLANT LEVEL SERVICE
The cooling system is closed and designed to main-
tain coolant level to the top of the radiator.
When servicing requires a coolant level check in
the radiator, the engine must beoffandnotunder
pressure. Drain several ounces of coolant from the
radiator draincock while observing the CoolantRecovery System (CRS) Tank. Coolant level in the
CRS tank should drop slightly. Then remove the radi-
ator cap. The radiator should be full to the top. If
not, and the coolant level in the CRS tank is at the
MIN mark there is an air leak in the CRS system.
Check hose or hose connections to the CRS tank,
radiator filler neck or the pressure cap seal to the
radiator filler neck for leaks.
COOLING SYSTEMÐDRAINING
Without removing radiator pressure cap and
with system not under pressure,shut engine off
and open draincock. The coolant reserve tank should
empty first, then remove radiator pressure cap. (if
not, see Testing Cooling System for leaks). To vent
2.4L engine remove the coolant temperature sensor
located above water outlet housing (Fig. 15). The 3.0/
3.3/3.8L engines have an air bleed vent on the ther-
mostat.
Removal of a sensor is required because the ther-
mostat does not have an air vent. Sensor removal
allows an air bleed for coolant to drain from the
engine block.
COOLING SYSTEMÐREFILLING
First clean system to remove old coolant, see Cool-
ing System Cleaning.
Fill the system, using the correct antifreeze as
described in the Coolant Section. Fill the system to
50 percent of its capacity with 100 percent glycol.
Then complete filling system with water. The 2.4L
engine requires venting by removal of the coolant
sensor on top of the water outlet connector (Fig. 15).
When coolant reaches this hole:
²Install coolant sensor and tighten to 7 N´m (60
in. lbs.) for 2.4L Engines.
Fig. 15 Coolant Temperature SensorÐ2.4L Engine
Drain/Fill
7 - 16 COOLING SYSTEMNS
DIAGNOSIS AND TESTING (Continued)
NOTE: It is normal for the water pump to weep a
small amount of coolant from the weep hole (black
stain on water pump body). Do not replace the
water pump if this condition exists. Replace the
water pump if a heavy deposit or a steady flow of
green/brown engine coolant is evident on water
pump body from the weep hole (shaft seal failure).
Be sure to perform a thorough analysis before
replacing water pump.
ACCESSORY DRIVE BELT
When inspecting serpentine drive belts, small
cracks that run across the ribbed surface of the belt
from rib to rib (Fig. 37), are considered normal. these
are not reasons to replace the belt. However, cracks
running along the rib (not across) are not normal.
Any belt with cracks running along the rib must be
replaced (Fig. 37). Also replace the belt if it has
excessive wear, frayed cords or severe glazing.
RADIATOR PRESSURE CAP
INSPECTION
Hold the cap in hand,right side up. The vent
valve at the bottom of the cap should open. If the
rubber gasket has swollen and prevents the valve
from opening, replace the cap.
Hold the cleaned cap in handupside down.If any
light shows between vent valve and rubber gasket,
replace cap.Do not use a replacement cap that
has a spring to hold the vent shut.
Replacement cap must be of the type designed for
coolant reserve system with a completely sealed dia-
phragm spring, and rubber gasket to seal to fillerneck top surface. This design assures coolant return
to radiator.
COOLING SYSTEM CLEANING
Drain cooling system (see:Cooling System
Draining) and refill with clean water (see:Cooling
System Refilling). Run engine with radiator cap
installed until upper radiator hose is hot. Stop
engine and drain water from system. If water is
dirty; fill, run, and drain system again, until water
runs clear.
REVERSE FLUSHING THE RADIATOR
Drain cooling system and remove radiator hoses
from engine. Install suitable flushing gun in radiator
lower hose. Fill radiator with clean water and turn
on air in short blasts.
CAUTION: Internal radiator pressure must not
exceed 138 kPa (20 psi) as damage to radiator may
result. Continue this procedure until water runs
clear.
REVERSE FLUSHING THE ENGINE
Drain radiator (see:Draining Cooling System)
and remove hoses from radiator. Remove engine ther-
mostat and reinstall thermostat housing. Install suit-
able flushing gun to thermostat housing hose. Turn
on water, and when engine is filled, turn on air, but
no higher than 138 kPa (20 psi) in short blasts. Allow
engine to fill between blasts of air. Continue this pro-
cedure until water runs clean. Reinstall thermostat
using a new housing gasket. Fill cooling system (See
Refilling).
CHEMICAL CLEANING
One type of corrosion encountered with aluminum
cylinder heads is aluminum hydroxide deposits. Cor-
rosion products are carried to the radiator and depos-
ited when cooled off. They appear as dark grey when
wet and white when dry. This corrosion can be
removed with a two part cleaner (oxalic acid and
neutralizer) available in auto parts outlets. Follow
manufacturers directions for use.
ADJUSTMENTS
PROPER BELT TENSION
Satisfactory performance of the belt driven accesso-
ries depends on proper belt tension. Belt tensioning
should be performed with the aid of a Burroughs
gauge Special Tool C-4162. Because of space limita-
tions in the engine compartment, the use of the
gauge may be restricted. Raise the vehicle on a hoist
Fig. 37 Serpentine Drive Belt Wear Patterns
NSCOOLING SYSTEM 7 - 25
CLEANING AND INSPECTION (Continued)
and the remove the splash shield to gain access to
the drive belts.
BELT TENSION GAUGE METHOD
Use belt tensioning Special Tool Kit C-4162 for:
CAUTION: The Burroughs gauge for the Poly-V
belt is not to be used on the V-belt. These gauges
are not interchangeable.
²For conventional V-belts affix the Burroughs
gauge (Special Tool C-4162) to the belt. Adjust the
belt tension for New or Used belt as prescribed in the
Belt Tension Chart.
²For a Poly-V belt affix the Poly-V Burroughs
gauge to the belt and then apply specified tension to
the belt as prescribed in the Belt Tension Chart
Adjust belt tension for aNeworUsedbelt as pre-
scribed in the Belt Tension Chart.
BELT TENSION CHARTSPECIFICATIONS
COOLING SYSTEM CAPACITY
TORQUE CHART
DESCRIPTION TORQUE
Thermostat Housing
BoltsÐ2.4L & 3.3/3.8L......28N´m(250 in. lbs.)
BoltsÐ3.0L...............12N´m(105 in. lbs.)
Water Pump Mounting
BoltsÐ2.4L & 3.3/3.8L......12N´m(250 in. lbs.)
BoltsÐ3.0L...............27N´m(240 in. lbs.)
Water Pump Inlet Tube
BoltsÐ2.4L...............12N´m(250 in. lbs.)
BoltsÐ3.0L................11N´m(94in.lbs.)
Water Pump Pulley
BoltsÐ3.3/3.8L............28N´m(250 in. lbs.)
Transaxle Oil Cooler Hose
ClampsÐAll Engines.........2N´m(18in.lbs.)
Radiator Mounting Upper Bracket
NutÐAll Engines..........12N´m(105 in. lbs.)
SPECIAL TOOLS
COOLING
ACCESSORY DRIVE
BELTGAUGE
2.4L ENGINE
A/C COMPRESSOR /
GENERATORNEW 190 LB.
USED 115 LB.
POWER STEERING NEW 140 LB.
USED 90 LB.
3.0L ENGINE
A/C COMPRESSOR NEW 150 LB.
USED 80 LB.
GENERATOR / POWER
STEERINGDYNAMIC TENSIONER
3.3/3.8L ENGINES
A/C COMPRESSOR DYNAMIC TENSIONER
GENERATOR / WATER
PUMP / POWER
STEERINGDYNAMIC TENSIONER
Engine Standard Duty Trailer Tow or
Heavy Duty
Front
HeaterRear
HeaterFront
HeaterRear
Heater
2.4L 10.6
liters*
(11.23
qts.)*N/A N/A N/A
3.0L 12.3
liters*
(13.0
qts.)*N/A N/A 15.0
liters*
(15.9
qts.)*
3.3/3.8L 12.5
liters*15.26
liters*12.5
liters*15.26
liters*
(13.23
qts.)*(16.13
qts.)*(13.23
qts.)*(16.13
qts)*
*Includes Heater and Coolant Recovery Tank Filled to
Max Level.
Belt Tension Gauge C-4162
7 - 26 COOLING SYSTEMNS
ADJUSTMENTS (Continued)
COOLING SYSTEM
CONTENTS
page page
GENERAL INFORMATION
COOLANT PRESSURE BOTTLE............ 1
COOLING SYSTEM Ð 2.0L GASOLINE...... 1
COOLING SYSTEM Ð 2.5L VM DIESEL..... 1
LOW COOLANT LEVEL SENSOR........... 1
RADIATOR............................ 2
DESCRIPTION AND OPERATION
AUTOMATIC BELT TENSIONER............ 6
BELT TENSION......................... 5
COOLANT PERFORMANCE............... 5
PRESSURE/VENT CAP................... 4
THERMOSTAT OPERATION............... 4
THERMOSTAT......................... 6
WATER PUMP......................... 3
SERVICE PROCEDURES
ADDING ADDITIONAL COOLANT........... 7
DRAINING COOLING SYSTEM............. 7
REFILLING COOLING SYSTEM............ 7
REMOVAL AND INSTALLATION
ENGINE THERMOSTATÐ 2.0L GASOLINE . . . 9GENERATOR/POWER STEERING BELT Ð 2.5L
VM DIESEL......................... 10
RADIATOR Ð 2.5L VM DIESEL........... 9
THERMOSTAT Ð 2.5L VM DIESEL......... 9
WATER PUMP BELT Ð 2.5L VM DIESEL . . . 10
WATER PUMP Ð 2.0L GASOLINE......... 7
WATER PUMP Ð 2.5L VM DIESEL........ 8
CLEANING AND INSPECTION
WATER PUMP........................ 10
ADJUSTMENTS
BELT TENSION CHART................. 11
BELT TENSION GAUGE METHOD......... 11
SPECIFICATIONS
COOLING SYSTEM CAPACITY............ 12
TORQUE CHART...................... 12
SPECIAL TOOLS
COOLING............................ 12
GENERAL INFORMATION
COOLING SYSTEM Ð 2.0L GASOLINE
The 2.0L gasoline engine cooling system consists of
an engine cooling module, thermostat, coolant, a
water pump to circulate the coolant. The engine cool-
ing module may consist of a radiator, electric fan
motors, fan, shroud, coolant reserve system, hoses,
clamps, air condition condenser.
²When the Engine is cold: The thermostat is
closed; the cooling system has no flow through the
radiator. The coolant flows through the engine,
heater system and bypass.
²When the Engine is warm: Thermostat is open;
the cooling system has flow through radiator, engine,
heater system and bypass.
COOLING SYSTEM Ð 2.5L VM DIESEL
The cooling system has a radiator, coolant, electric
fan motors, shroud, pressure cap, thermostat, coolant
pressure bottle, hoses, a water pump to circulate the
coolant, to complete the circuit. Coolant flow for the
VM diesel engine is shown in (Fig. 1).
COOLANT PRESSURE BOTTLE
2.5L VM DIESEL
This system works with the pressure cap to use
thermal expansion and contraction of the coolant to
keep the coolant free of trapped air. It provides some
reserve coolant to cover minor leaks and evaporation
or boiling losses. The coolant pressure bottle location
for 2.5L diesel is above the cylinder head cover (Fig.
2).
LOW COOLANT LEVEL SENSOR
The low coolant level sensor checks for low coolant
level in the coolant tank. A signal will be sent from
this sensor to the Body Control Module (BCM). When
the BCM determines low coolant level for 30 contin-
uous seconds, the instrument panel mounted low
coolant level warning lamp will be illuminated. The
sensor is located on the front side of the coolant tank
(Fig. 4). For information, refer to Group 8E, Instru-
ment Panel and Gauges.
If this lamp is illuminated, it indicates the need to
fill the coolant tank and check for leaks.
NS/GSCOOLING SYSTEM 7 - 1
RADIATOR
The radiators are cross-flow types (horizontal
tubes) with design features that provide greater
strength along with sufficient heat transfer capabili-
Fig. 1 Cooling System Operation ± 2.5L VM Diesel
Fig. 2 Coolant Pressure Bottle ± 2.5L VM Diesel
Fig. 3 Low Coolant Warning Sensor Connector ±
2.5L VM Diesel
7 - 2 COOLING SYSTEMNS/GS
GENERAL INFORMATION (Continued)
THERMOSTAT OPERATION
2.5 VM DIESEL
The engine cooling thermostats are wax pellet
driven, reverse poppet choke type. They are designed
to provide the fastest warm up possible by prevent-
ing leakage through them and to guarantee a mini-
mum engine operating temperature (Fig. 10). The
thermostat has a hole to bleed off air in the cooling
system during engine warm up. The thermostat
begins to open at 80É C62É (176É F64É).
PRESSURE/VENT CAP
WARNING: Engine coolant can reach temperatures
of 200É fahrenheit or greater. If the cooling system
is opened with coolant at a high temperature, hot
coolant can be forced out of the system under high
pressures, causing personal injury. Allow system to
cool down prior to removing the pressure cap.
The pressure/vent cap is secured to the coolant
tank neck by a means of a cam lock system. This cap
releases excess pressure at some point within a
range of 90-117 kPa (13- 17 psi) for gasoline engines,
and 110±124 kPa (16±18 psi) for diesel engines. The
actual pressure relief point (in pounds) is labeled on
top of the cap (Fig. 11).
The cooling system will operate at pressures
slightly above atmospheric pressure. This results in a
higher coolant boiling point allowing increased radi-
ator cooling capacity. The cap (Fig. 11) contains a
spring-loaded pressure relief valve. This valve opens
when system pressure reaches approximately 103
kPa (15 psi).
When the engine is cooling down, vacuum is
formed within the cooling system. To prevent collapse
of the radiator and coolant hoses from this vacuum, a
vacuum valve is used within the cap. This valve pre-
vents excessive pressure differences from occurring
between the closed cooling system and the atmo-
sphere. If the vacuum valve is stuck shut, the radia-
tor and/or cooling system hoses will collapse on cool-
down.
Fig. 7 Water PumpÐ2.0L Gasoline Engine
Fig. 8 Water PumpÐ2.0L Gasoline Engine
Fig. 9 Water PumpÐ2.5L VM Diesel
Fig. 10 Thermostat and Housing Ð 2.5L VM Diesel
7 - 4 COOLING SYSTEMNS/GS
DESCRIPTION AND OPERATION (Continued)
SERVICE PROCEDURES
ADDING ADDITIONAL COOLANT
2.5L VM DIESEL
Do not remove coolant bottle pressure cap when
the engine is hot. Remove pressure cap and fill cool-
ant bottle between Min and Max lines inside filler
neck. Use only 50/50 mix of ethylene glycol type anti-
freeze and water (Fig. 13). Squeezing radiator hoses
may help purge air from the cooling system.
DRAINING COOLING SYSTEM
2.0L GASOLINE
To drain cooling system move temperature selector
for heater to full heat with engine running.Without
removing radiator pressure cap and with sys-
tem not under pressure,Shut engine off and open
draincock. The coolant reserve tank should empty
first, then remove radiator pressure cap and let the
radiator drain (if not, see Testing Cooling System for
leaks).
2.5L VM DIESEL
The cooling system does not have a radiator
mounted pressure cap. Instead the pressure cap is
mounted on the coolant pressure bottle (Fig. 14).
(1) Shut off engine.
(2) Remove radiator pressure cap.
(3) Open draincock and allow coolant to drain.
REFILLING COOLING SYSTEM
2.0L GASOLINE
Refer to the gasoline engine cooling system infor-
mation in this manual. Cooling system capacity is 6.0
liters (6.34 qts.) which includes the heater and cool-
ant recovery tank.
2.5L VM DIESEL
First clean system to remove old glycol, see Cooling
System Cleaning.
(1) Disconnect upper radiator hose at thermostat
housing.
(2) Remove pressure cap from coolant expansion
tank.
(3) Fill cooling system through upper radiator hose
until coolant starts to leak out at the thermostat
housing. Reconnect hose and re-install clamp.
(4) Fill expansion tank to top of bottle. Run engine
at idle without pressure cap installed for 5 minutes.
Squeeze upper radiator hose several times.
(5) Shut off engine. Top off coolant and install
pressure cap.
(6) Inspect system for leaks.
REMOVAL AND INSTALLATION
WATER PUMP Ð 2.0L GASOLINE
REMOVAL
(1) Remove accessory drive belts and power steer-
ing pump.
(2) Drain cooling system.
Fig. 13 Coolant Pressure BottleÐ2.5L VM Diesel
Fig. 14 Pressure Cap and BottleÐVM Diesel
NS/GSCOOLING SYSTEM 7 - 7
SPECIFICATIONS
COOLING SYSTEM CAPACITY
TORQUE CHART
SPECIAL TOOLS
COOLING
2.0L Gasoline *10.6 liters (11 qts.)
2.5L VM Diesel *10.0 liters (10.6 qts.)
*Includes Heater and Coolant recovery/pressure Tank.
COMPONENT 2.0L
GASOLINE2.5L VM
Thermostat
Cover Bolts105 in-lbs 10.8 N´m (96 in.
lbs.)
Water Pump
Mounting Bolts12 N´m (105 in.
lbs.)22.6 N´m (204
in. lbs.)
Water Pump
Pulley BoltsN/A 27.5 N´m (240
in. lbs.)
Upper Radiator
Mounting
Bracket Bolts12 N´m (105 in.
lbs.)12 N´m (105 in.
lbs.)
Turbocharger
Oil Supply LineN/A 24.5 N´m (215
in. lbs.)
Turbocharger
Oil Return LineN/A 10.8 N´m (96 in.
lbs.)
Water Pump
Housing NutsN/A 9.5 N´m (84 in.
lbs.)
Water Manifold
BoltsN/A 11.2 N´m (96 in.
lbs.)
Coolant Bottle
Bolts2.0 N´m (18 in.
lbs.)10.8 N´m (96 in.
lbs.)
Belt Tension Gauge C-4162
7 - 12 COOLING SYSTEMNS/GS