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)
INSTALLATION
(1) Clean all gasket and O-ring surfaces on pump
and water pipe inlet tube.
(2) Install new O-ring on water inlet pipe (Fig.
22). Wet the O-ring (with water) to ease assembly.
CAUTION: Keep the O-ring free of oil or grease.
(3) Install new gasket on water pump and install
pump inlet opening over water pipe, press assembly
to cause water pipe insertion into pump housing.
(4) Install pump to block mounting bolts and
tighten to 27 N´m (20 ft. lbs.).
(5) See Timing Belt in Engine, Group 9 and
install timing belt. Reassemble engine.
(6) Fill cooling system. See Refilling Cooling Sys-
tem.
WATER PUMPÐ3.3/3.8L ENGINES
REMOVAL
(1) Drain Cooling System. Refer to Draining Cool-
ing System in this group.
(2) Remove Poly-V Drive Belt.
(3) Remove right front lower fender shield.
(4) Remove pump pulley bolts and remove pulley.
(5) Remove pump mounting screws (Fig. 23).
Remove water pump.
(6) Remove and discard O-ring seal.
(7) Clean O-ring groove and O-ring surfaces on
pump and chain case cover. Take care not to scratch
or gouge sealing surface.
INSTALLATION
(1) Install new O-ring into groove (Fig. 24).
(2) Install pump to chain case cover. Torque
screws to 12 N´m (105 in. lbs.)
(3) Rotate pump by hand to check for freedom of
movement.(4) Position pulley on pump. Install screws and
torque to 30 N´m (250 in. lbs.).
(5) Install drive belt. See Accessory Drive Belts in
this group.
(6) Install right front lower fender shield.
(7) Refill Cooling System. See Refilling Cooling
System.
THERMOSTATÐ2.4L ENGINE
REMOVAL
(1) Drain cooling system down below the thermo-
stat level. Refer to Draining Cooling System in this
group.
(2) Remove thermostat housing bolts and housing
(Fig. 25).
(3) Remove thermostat, discard gasket and clean
both gasket sealing surfaces.
Fig. 23 Water Pump Ð3.3/3.8L Engines
Fig. 24 Water Pump Body
Fig. 25 Thermostat, Housing, and Outlet
ConnectorÐ2.4L Engine
NSCOOLING SYSTEM 7 - 19
REMOVAL AND INSTALLATION (Continued)
INSTALLATION
(1) Place a new gasket (dipped in water) on the
thermostat housing surface, center thermostat into
opening in the intake manifold water box.
(2) Place housing and gasket over the thermostat,
making sure thermostat is in the recess provided
(Fig. 28).
(3) Bolt housing to intake manifold, tighten bolts
to 28 N´m (250 in. lbs.).
(4) Refill the cooling system to the proper level.
Refer to Cooling System Refilling outlined in this sec-
tion for procedure.
RADIATOR
REMOVAL
(1) Disconnect negative cable from battery.
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.
(2) Drain cooling system. Refer to Draining Cool-
ing System of this section.
(3) Remove air intake resonator.
(4) Remove coolant reserve system tank to filler
neck tube hose.
(5) Disconnect fans from the connector located on
the left side of the fan module.
(6) Remove the Coolant Recovery System (CRS)
tank retaining screw from the upper radiator closure
panel crossmember.
(7) Disconnect the upper radiator mounting
screws from the crossmember. Disconnect the engine
block heater wire if equipped.
(8) Remove the upper radiator closure panel
crossmember. Refer to Group 23 Body for procedure.
(9) Remove air cleaner assembly.
(10) Disconnect automatic transmission oil cooler
lines at radiator and plug.
(11) Disconnect inlet and outlet hoses from the
radiator. Remove the lower hose clip from the fan
module.
(12) Remove A/C condenser fasteners and sepa-
rate the condenser from the radiator (Fig. 29). Verify
the condenser is supported in position.
(13) Remove A/C filter/dryer mounting bracket, 2
bolts to the fan module, and 2 nuts to the filter/dryer.
(14) Radiator can now be lifted free from engine
compartment.Care should be taken not to dam-
age radiator cooling fins or water tubes during
removal.INSTALLATION
(1)Be sure the air seals are in position before
radiator is installed.Slide radiator down into posi-
tion behind closure panel. Seat the radiator with the
rubber isolators into the mounting holes provided,
with a 10 lbs. force.
(2) Install A/C filter/dryer and mounting bracket
onto fan module.
(3) Install Air Conditioning Condenser onto the
radiator (Fig. 29).
(4) Unplug and connect automatic transmission
oil cooler lines to radiator.
(5) Install inlet and outlet radiator hoses (includ-
ing coolant reserve hose) and connect the fan motor
electrical connection.
(6) Install air cleaner assembly.
(7) Install the upper radiator closure panel cross-
member. Refer to Group 23 Body for procedure.
(8) Install the upper radiator mounting screws.
Tighten radiator mounting bolts to 12 N´m (105 in.
lbs.). Connect the engine block heater wire if
equipped.
(9) Install the Coolant Recovery System (CRS)
tank retaining screw to the upper radiator closure
panel crossmember.
(10) Install air intake resonator.
(11) Fill cooling system. Refer to Cooling System
Filling in this section.
(12) Connect negative cable to battery.
RADIATOR DRAINCOCK
REMOVAL
CAUTION: Use of pliers on draincock is not rec-
ommended. Damage may occur to part. Draincock
should not be removed unless leakage observed.
(1) Turn the draincock stem counterclockwise to
unscrew the stem. When the stem is unscrewed to
Fig. 29 Air Conditioning Condenser Mounting
Fasteners
NSCOOLING SYSTEM 7 - 21
REMOVAL AND INSTALLATION (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
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)
NOTE: Do not use any type of tool when tighten-
ing the cap. Hand tighten only (approximately 5 N´m
or 44 in. lbs.) torque.
COOLANT PERFORMANCE
ETHYLENE-GLYCOL MIXTURES
The required ethylene-glycol (antifreeze) and water
mixture depends upon the climate and vehicle oper-
ating conditions. The recommended mixture of 50/50
ethylene-glycol and water will provide protection
against freezing to -37 deg. C (-35 deg. F). The anti-
freeze concentrationmust alwaysbe a minimum of
44 percent, year-round in all climates.If percentage
is lower than 44 percent, engine parts may be
eroded by cavitation, and cooling system com-
ponents may be severely damaged by corrosion.
Maximum protection against freezing is provided
with a 68 percent antifreeze concentration, which
prevents freezing down to -67.7 deg. C (-90 deg. F). A
higher percentage will freeze at a warmer tempera-
ture.100 Percent Ethylene-GlycolÐShould Not Be Used in
Chrysler Vehicles
Use of 100 percent ethylene-glycol will cause for-
mation of additive deposits in the system, as the cor-
rosion inhibitive additives in ethylene-glycol require
the presence of water to dissolve. The deposits act as
insulation, causing temperatures to rise to as high as
149 deg. C (300) deg. F). This temperature is hot
enough to melt plastic and soften solder. The
increased temperature can result in engine detona-
tion. In addition, 100 percent ethylene-glycol freezes
at 22 deg. C (-8 deg. F ).
Propylene-glycol FormulationsÐShould Not Be Used in
Chrysler Vehicles
Propylene-glycol formulations do not meet
Chrysler coolant specifications.It's overall effec-
tive temperature range is smaller than that of ethyl-
ene-glycol. The freeze point of 50/50 propylene-glycol
and water is -32 deg. C (-26 deg. F). 5 deg. C higher
than ethylene-glycol's freeze point. The boiling point
(protection against summer boil-over) of propylene-
glycol is 125 deg. C (257 deg.F)at96.5 kPa (14 psi),
compared to 128 deg. C (263 deg. F) for ethylene-gly-
col. Use of propylene-glycol can result in boil-over or
freeze-up in Chrysler vehicles, which are designed for
ethylene-glycol. Propylene glycol also has poorer heat
transfer characteristics than ethylene glycol. This
can increase cylinder head temperatures under cer-
tain conditions.
Propylene-glycol/Ethylene-glycol MixturesÐShould Not Be
Used in Chrysler Vehicles
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.
CAUTION: Richer antifreeze mixtures cannot be
measured with normal field equipment and can
cause problems associated with 100 percent ethyl-
ene-glycol.
BELT TENSION
Correct accessory drive belt tension is required to
be sure of optimum performance of belt driven engine
accessories. If specified tension is not maintained,
belt slippage may cause; engine overheating, lack of
power steering assist, loss of air conditioning capac-
ity, reduced generator output rate and greatly
reduced belt life.
Fig. 11 Coolant Tank Pressure/Vent Cap
NS/GSCOOLING SYSTEM 7 - 5
DESCRIPTION AND OPERATION (Continued)
Initial belt adjustment is done with a adjustable
tensioner pulley. After the initial adjustment is per-
formed, an automatic belt tensioner is used to main-
tain correct belt tension at all times. Do not attempt
to check belt tension with a belt tension gauge on
vehicles equipped with an automatic belt tensioner.
Refer to Automatic Belt Tensioner in this group.
AUTOMATIC BELT TENSIONER
Drive belt tension is controlled by a spring loaded
automatic belt tensioner located below and to the
front of the engine oil filter (Fig. 12). This tensioner
is connected to a pivot bracket and a pulley (Fig. 12).
The pivot bracket rotates on a pivot pin attached to
the engine. Special machined washers with rubber
o-rings (Fig. 12) are used at each side of the pivot
bracket to help keep dirt and water away from the
pivot pin.
If a defective belt tensioner is suspected, a check of
this pivot bracket and pivot pin should be made. Cor-
rosion may have formed at the pin and may cause
the pivot bracket to stick. Belt slippage will result.
WARNING: BECAUSE OF HIGH SPRING PRES-
SURE, DO NOT ATTEMPT TO DISASSEMBLE THE
AUTOMATIC BELT TENSIONER. UNIT IS SERVICED
AS AN ASSEMBLY.
THERMOSTAT
DIAGNOSIS
Diesel engines, due to their inherent efficiency are
slower to warm up than gasoline powered engines,
and will operate at lower temperatures when the
vehicle is unloaded. Because of this, lower tempera-
ture gauge readings for diesel versus gasoline
engines may, at times be normal.
Typically, complaints of low engine coolant temper-
ature are observed as low heater output when com-
bined with cool or cold outside temperatures.
To help promote faster engine warm-up, an electric
engine block heater must be used with cool or cold
outside temperatures. This will help keep the engine
coolant warm when the vehicle is parked. Use the
block heater if the outside temperature is below 4ÉC
(40ÉF).Do not use the block heater if the out-
side temperature is above 4ÉC (40ÉF).
TESTING
NOTE: The DRB scan tool shoud be used to moni-
tor engine coolant temperature on the diesel
engine. Refer to the 1998 GS Powertrain Diagnostic
Manual for thermostat diagnosis procedure.
Fig. 12 Automatic Belt Tensioner Assembly
7 - 6 COOLING SYSTEMNS/GS
DESCRIPTION AND OPERATION (Continued)