engine coolant CHRYSLER VOYAGER 2004 Owner's Manual

(Fig. 12). The ICU is located below the master cylin-
der in the engine compartment (Fig. 13).
Two different ICU's (HCU and CAB) are used on
this vehicle depending on whether or not the vehicle
is equipped with traction control. The HCU on a
vehicle equipped with traction control has a valve
block that is approximately one inch longer than a
HCU on a vehicle that is equipped with ABS only.
The ABS-only ICU consists of the following compo-
nents: the CAB, eight (build/decay) solenoid valves
(four inlet valves and four outlet valves), valve block,
fluid accumulators, a pump, and an electric motor.
The ABS-with traction control ICU consists of the
following components: the CAB, eight (build/decay)solenoid valves (four inlet valves and four outlet
valves), two traction control (ASR) valves, two
hydraulic shuttle valves, valve block, fluid accumula-
tors, a pump, and an electric motor.
The replaceable components of the ICU are the
HCU and the CAB. No attempt should be made to
service any individual components of the HCU or
CAB. For information on the CAB, (Refer to 8 -
ELECTRICAL/ELECTRONIC CONTROL MOD-
ULES/CONTROLLER ANTILOCK BRAKE -
DESCRIPTION).
OPERATION
For information of the ICU, refer to these individ-
ual components of the ICU:
²CONTROLLER ANTILOCK BRAKE (CAB)
(Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/CONTROLLER ANTILOCK
BRAKE - OPERATION)
²HYDRAULIC CONTROL UNIT (HCU) (Refer to
5 - BRAKES - ABS/HYDRAULIC/MECHANICAL/
HCU (HYDRAULIC CONTROL UNIT) - OPERA-
TION)
For information on the ICU's hydraulic circuits,
refer to HYDRAULIC CIRCUITS AND VALVE
OPERATION. (Refer to 5 - BRAKES - ABS/HY-
DRAULIC/MECHANICAL - OPERATION)
REMOVAL
REMOVAL - LHD
(1) Disconnect the negative (ground) cable from
the battery and isolate cable.
(2) Remove the battery shield.
(3) Remove the battery (Refer to 8 - ELECTRI-
CAL/BATTERY SYSTEM/BATTERY - REMOVAL).
(4) Disconnect the vacuum hose connector at the
tank built into the battery tray.
(5) Remove the screw securing the engine coolant
filler neck to the battery tray.
(6) Remove the battery tray (Refer to 8 - ELEC-
TRICAL/BATTERY SYSTEM/TRAY - REMOVAL).
(7) Using a brake pedal depressor, move and lock
the brake pedal to a position past the first inch of
pedal travel.This will prevent brake fluid from
draining out of the master cylinder once the
brake tubes are removed from the HCU.
CAUTION: Do not apply a 12±volt power source to
any terminals of the 24-way CAB connector when
disconnected.
(8) Disconnect the wiring harness connector from
the speed control servo.
(9) Remove the speed control servo mounting nuts
and move the servo out of the way.
Fig. 12 INTEGRATED CONTROL UNIT (ICU)
1 - PUMP/MOTOR
2 - HCU
3 - PUMP/MOTOR CONNECTOR
4 - CAB
Fig. 13 ICU LOCATION IN VEHICLE
1 - POWER BRAKE BOOSTER
2 - MASTER CYLINDER
3 - ICU
5 - 90 BRAKES - ABSRS
ICU (INTEGRATED CONTROL UNIT) (Continued)

Use only brake fluid that was stored in a tightly-
sealed container. DO NOT use petroleum-based fluid because seal
damage will result. Petroleum based fluids would be
items such as engine oil, transmission fluid, power
steering fluid etc.
SPECIFICATIONS
BRAKE FLUID
The brake fluid used in this vehicle must conform
to DOT 3 specifications (DOT 4 and DOT 4+ are
acceptable) and SAE J1703 standards. No other type
of brake fluid is recommended or approved for usage
in the vehicle brake system. Use only Mopar tBrake
Fluid or equivalent from a tightly sealed container.
CAUTION: Never use reclaimed brake fluid or fluid
from an container which has been left open. An
open container of brake fluid will absorb moisture
from the air and contaminate the fluid.
CAUTION: Never use any type of a petroleum-based
fluid in the brake hydraulic system. Use of such
type fluids will result in seal damage of the vehicle
brake hydraulic system causing a failure of the
vehicle brake system. Petroleum based fluids would
be items such as engine oil, transmission fluid,
power steering fluid, etc.
JUNCTION BLOCK
DESCRIPTION - NON-ABS JUNCTION BLOCK
A junction block is used on vehicles that are not
equipped with antilock brakes (ABS). The junction
block mounts in the same location as the integrated
control unit (ICU) does on vehicles equipped with
ABS. This allows for use of the same brake tube con-
figuration on all vehicles. The junction block is located
on the driver's side of the front suspension cradle/
crossmember below the master cylinder (Fig. 44).
It has six threaded ports to which the brake tubes
connect. Two are for the primary and secondary
brake tubes coming from the master cylinder. The
remaining four are for the chassis brake tubes going
to each brake assembly.
OPERATION - NON-ABS JUNCTION BLOCK
The junction block distributes the brake fluid com-
ing from the master cylinder primary and secondary
ports to the four chassis brake tubes leading to the
brakes at each wheel. Since the junction block
mounts in the same location as the ABS integrated control unit (ICU), it allows for the common use of
brake tubes going to the brakes whether the vehicle
is equipped with or without ABS.
NOTE: Although the brake tubes coming from the
master cylinder to the junction block or ABS ICU
may appear to be the same, they are not. They are
unique to each brake system application.
REMOVAL - NON-ABS JUNCTION BLOCK
(1) Using a brake pedal depressor, move and lock
the brake pedal to a position past its first 1 inch of
travel. This will prevent brake fluid from draining
out of the master cylinder when the brake tubes are
removed from the junction block. (2) Disconnect the battery negative cable.
(3) If the vehicle is equipped with speed control,
perform the following: (a) Disconnect the battery positive cable.
(b) Remove the battery (Refer t o 8 - ELECTRI-
CAL/BATTERY SYSTEM/BATTERY - REMOVAL). (c) Disconnect the vacuum hose connector at the
tank built into the battery tray. (d) Remove the screw securing the coolant filler
neck to the battery tray. (e) Remove the battery tray (Refer t o 8 - ELEC-
TRICAL/BATTERY SYSTEM/TRAY - REMOVAL). (f) Remove the fasteners and move the speed
control servo off to the side, out of the way.
CAUTION: Before removing the brake tubes from
the junction block, the junction block and the brake
tubes must be thoroughly cleaned. This is required
to prevent contamination from entering the brake
hydraulic system. (4) Remove the four chassis brake tubes from the
top of the junction block (Fig. 44). (5) Remove the primary and secondary brake
tubes from the top of the junction block. (6) Remove the bolts attaching the junction block
mounting bracket to the front suspension crossmem-
ber (Fig. 44), then remove the junction block.
INSTALLATION - NON-ABS JUNCTION BLOCK
(1) Install the junction block and mounting bracket
on the front suspension crossmember (Fig. 44).
Install the mounting bolts and tighten to a torque of
28 N´m (250 in. lbs.). (2) Install the primary and secondary brake tubes
from the master cylinder in their ports. Tighten tube
nuts to a torque of 17 N´m (145 in. lbs.). Take care
not to twist tubes when tightening tube nuts.
They must be properly positioned to allow free
movement with rubber isolated suspension
crossmember.
5s - 32 BRAKESRS
FLUID (Continued)

(3) Install the four chassis brake tubes into the
outlet ports of the junction block. Tighten all 6 tube
nuts to a torque of 17 N´m (145 in. lbs.). (4) If the vehicle is equipped with speed control,
perform the following: (a) Install the speed control servo with its
mounting nuts. (b) Connect the wiring harness to the speed con-
trol servo. (c) Install the battery tray (Refer t o 8 - ELEC-
TRICAL/BATTERY SYSTEM/TRAY - INSTALLA-
TION). (d) Install the screw securing the coolant filler
neck to the battery tray. (e) Reconnect the vacuum hose connector at the
tank built into the battery tray. (f) Install the battery (Refer t o 8 - ELECTRI-
CAL/BATTERY SYSTEM/BATTERY - INSTALLA-
TION). (g) Install the battery shield.
(5) Remove the brake pedal holder.
(6) Connect negative cable back on negative post of
the battery. (7) Bleed the brake system thoroughly to ensure
that all air has been expelled from the hydraulic sys-
tem. (Refer t o 5 - BRAKES - STANDARD PROCE-
DURE). (8) Road test the vehicle to verify proper operation
of the brake system.
MASTER CYLINDER
DESCRIPTION
DESCRIPTION
The master cylinder is located on the power brake
booster in the engine compartment on the driver's
side (Fig. 45). This vehicle uses 3 different master
cylinders. Master cylinder usage depends on what
type of brake system the vehicle is equipped with.
CAUTION: Master cylinders are not interchangeable
between systems. Performance and stopping dis-
tance issues will result if the incorrect master cyl-
inder is installed on the vehicle.
For information on master cylinder application,
bore and type, view the following table:
BRAKE SYSTEM MASTER CYLINDER
BORE/TYPE
Disc/Drum - ABS 23.8 mm (15/16 in.)
Conventional
Compensating Port
Disc/Drum - Non-ABS 23.8 mm (15/16 in.)
Conventional
Compensating Port
Disc/Disc - ABS 25.4 mm (1.0 in.)
Conventional
Compensating Port
Disc/Disc ABS With
Traction Control 25.4 mm (1.0 in.) Dual
Center Port
Fig. 44 NON-ABS JUNCTION BLOCK
1 - MASTER CYLINDER
2 - JUNCTION BLOCK
3 - SUSPENSION CROSSMEMBER
4 - MOUNTING BOLTS
Fig. 45 Master Cylinder And Booster Location
1 - MASTER CYLINDER
2 - POWER BRAKE BOOSTER
RS BRAKES5s-33
JUNCTION BLOCK (Continued)

(6) Apply light effort (approximately 15 lbs. of
force) to the brake pedal and hold the pedal steady.
Do not move the pedal once the pressure is applied
or the test results may vary. (7) Have an assistant reattach the vacuum line
pliers to the vacuum supply hose. (8) Allow 5 seconds for stabilization, then observe
the vacuum gauge. If the vacuum drop exceeds 3.0 inches Hg (10 kPa)
in 15 seconds, repeat the above steps to confirm the
reading. The vacuum loss should be less than 3.0
inches Hg in 15 seconds time span. If the loss is
more than 3.0 inches Hg, replace the power brake
booster. If it is not, the booster is not defective. (9) Remove the pliers and vacuum gauge.
REMOVAL
REMOVAL - LHD
CAUTION: Reserve vacuum in power brake booster
must be pumped down (removed) before removing
master cylinder from booster. This is necessary to
prevent booster from sucking in any contamination
as master cylinder is removed. This can be done
simply by pumping the brake pedal, with the vehi-
cle's engine not running, until a firm feeling brake
pedal is achieved.
(1) With engine not running, pump the brake
pedal until a firm pedal is achieved (4-5 strokes). (2) Remove negative battery cable terminal from
battery. (3) Remove positive battery cable terminal from
battery. (4) Remove battery thermal guard shield.
(5) Remove battery clamp, nut and battery from
the battery tray. (6) Remove screw securing engine coolant filler
tube to battery tray. (7) If the vehicle is equipped with speed control,
disconnect the vacuum hose at the vacuum tank built
into the battery tray. (8) Remove the two nuts and one bolt securing bat-
tery tray in place. Remove battery tray. (9) If vehicle is equipped with speed control:(a) Disconnect wiring harness connector from
the speed control servo. (b) Remove the two servo mounting nuts.
(c) Lay speed control servo off to the side, out of
the way.
(10) Remove the wiper module (unit). (Refer to 8 -
ELECTRICAL/WIPERS/WASHERS/WIPER MOD-
ULE - REMOVAL) (11) Disconnect wiring harness connector from
brake fluid level switch in master cylinder fluid res-
ervoir (Fig. 66).
CAUTION: Before removing the master cylinder
from the power brake vacuum booster, the master
cylinder and vacuum booster must be thoroughly
cleaned. This must be done to prevent dirt particles
from falling into the power brake vacuum booster.
(12) Clean area where master cylinder assembly
attaches to power brake booster. Use only a solvent
such as Mopar tBrake Parts Cleaner or equivalent.
(13) Disconnect primary and secondary brake
tubes from ABS integrated control unit or non-ABS
junction block (Fig. 67). Install sealing plugs in the
now open brake tube ports and install caps on ends
of tubes.
NOTE: It is not necessary to remove the brake
tubes from the master cylinder when removing the
master cylinder from the vacuum booster.
(14) Remove two nuts attaching master cylinder to
power brake booster (Fig. 67). (15) Slide master cylinder straight out of power
brake booster. Remove master cylinder with primary
and secondary tubes from vehicle.
CAUTION: A seal on the rear of the master cylinder
is used to create the seal for holding vacuum in the
power brake vacuum booster. The vacuum seal on
the master cylinder MUST be replaced whenever the
master cylinder is removed from the power brake
vacuum booster.
Fig. 66 Master Cylinder And Booster
1 - POWER BRAKE BOOSTER
2 - BOOSTER IDENTIFICATION LABEL
3 - FLUID LEVEL SWITCH CONNECTOR
4 - PRIMARY BRAKE TUBE NUT
5 - SECONDARY BRAKE TUBE NUT
6 - MASTER CYLINDER
RS BRAKES5s-45
POWER BRAKE BOOSTER (Continued)

REMOVAL - RHD
CAUTION: Reserve vacuum in power brake booster
must be pumped down (removed) before removing
master cylinder from booster. This is necessary to
prevent booster from sucking in any contamination
as master cylinder is removed. This can be done
simply by pumping the brake pedal, with the vehi-
cle's engine not running, until a firm feeling brake
pedal is achieved.(1) With engine not running, pump the brake
pedal until a firm pedal is achieved (4 or 5 strokes). (2) Remove negative battery cable terminal from
battery. (3) Remove positive battery cable terminal from
battery. (4) Remove battery thermal guard shield.
(5) Remove battery clamp, nut and battery from
the battery tray. (6) If the vehicle is equipped with speed control,
disconnect the vacuum hose at the vacuum tank built
into the battery tray. (7) Remove the two nuts and one bolt securing bat-
tery tray in place. Remove battery tray. (8) If vehicle is equipped with speed control:(a) Disconnect wiring harness connector from
the speed control servo. (b) Remove the two servo mounting nuts.
(c) Lay speed control servo off to the side, out of
the way.
(9) If the vehicle is equipped with the 2.5L diesel
engine, remove the coolant recovery pressure con-
tainer and bracket. (Refer t o 7 - COOLING/ENGINE/
COOLANT RECOVERY PRESS CONTAINER -
REMOVAL) (10) Disconnect wiring harness connector from
brake fluid level switch in master cylinder fluid res-
ervoir (Fig. 71).
CAUTION: Before removing the master cylinder
from the power brake vacuum booster, the master
cylinder and vacuum booster must be thoroughly
cleaned. This must be done to prevent dirt particles
from falling into the power brake vacuum booster.
(11) Clean area where master cylinder assembly
attaches to power brake booster. Use only a solvent
such as Mopar tBrake Parts Cleaner or equivalent.
NOTE: It is not necessary to remove the brake
tubes from the master cylinder when removing the
master cylinder from the booster. (12) Remove two nuts attaching master cylinder to
power brake booster (Fig. 72). (13) Slide master cylinder straight out of power
brake booster. Lay master cylinder with primary and
secondary tubes to the side, out of the way.
CAUTION: A seal on the rear of the master cylinder
is used to create the seal for holding vacuum in the
power brake vacuum booster. The vacuum seal on
the master cylinder MUST be replaced whenever the
master cylinder is removed from the power brake
vacuum booster.
(14) Disconnect vacuum hose from check valve
located on booster. DO NOT REMOVE CHECK
VALVE FROM POWER BRAKE BOOSTER.
Fig. 71 RHD Master Cylinder And Power Brake Booster
1 - POWER BRAKE BOOSTER
2 - BRAKE FLUID LEVEL SWITCH
3 - FLUID RESERVOIR
4 - MASTER CYLINDER
Fig. 72 RHD Master Cylinder Mounting
1 - PRIMARY BRAKE TUBE NUT
2 - SECONDARY BRAKE TUBE NUT
3 - MASTER CYLINDER MOUNTING NUTS
RS BRAKES5s-47
POWER BRAKE BOOSTER (Continued)

the mounting nuts to a torque of 14 N´m (124 in.
lbs.).(16) Install the battery tray. Install the two nuts
and one bolt attaching the battery tray to the vehicle.
Tighten the bolt and nuts to a torque of 14 N´m (124
in. lbs.). (17) If vehicle is equipped with speed control, con-
nect the servo vacuum hose to the vacuum tank on
the battery tray. (18) Install the air inlet resonator and hoses as an
assembly on the throttle body and air cleaner hous-
ing. Securely tighten hose clamp at air cleaner hous-
ing and throttle body. (19) Secure the engine coolant filler neck to the
battery tray with its mounting screw. (20) Install the battery, clamp and mounting nut.
(21) Install the positive battery cable on the bat-
tery. (22) Install the negative battery cable on the bat-
tery. (23) Install the battery thermal guard shield.
(24) Bleed the base brakes as necessary. (Refer to
5 - BRAKES - STANDARD PROCEDURE) (25) Road test vehicle to ensure operation of the
brakes.
INSTALLATION - RHD
(1) Position power brake booster on dash panel
using the reverse procedure of its removal (Fig. 75). (2) Below instrument panel, first install the two
upper nuts mounting the booster to the dash panel,
drawing it into place, then install the two lower
mounting nuts. Tighten the mounting nuts to a
torque of 29 N´m (250 in. lbs.). (3) Using lubriplate, or equivalent, coat the sur-
face of the brake pedal torque shaft pin where it con-
tacts the booster input rod.
CAUTION: When installing the brake pedal torque
shaft pin on the power brake booster input rod, do
not re-use the old retaining clip.
(4) Install booster input rod on brake pedal torque
shaft pin and install a NEW retaining clip (Fig. 78). (5) Install booster input rod trim cover.
(6) Connect vacuum hose to check valve on power
brake booster.
CAUTION: The master cylinder (and its rear seal) is
used to create the seal for holding vacuum in the
vacuum booster. The vacuum seal on the master
cylinder MUST be replaced with a NEW seal when-
ever the master cylinder is removed from the vac-
uum booster. CAUTION: When removing the vacuum seal from
the master cylinder, do not use a sharp tool.
(7) Using a soft tool such as a trim stick, remove
the vacuum seal from the master cylinder mounting
flange. (8) Install a NEW vacuum seal on rear mounting
flange of the master cylinder (Fig. 79).
(9) Position master cylinder on studs of booster,
aligning push rod on booster with master cylinder
piston. (10) Install the two nuts mounting the master cyl-
inder to the booster (Fig. 72). Tighten both mounting
nuts to a torque of 25 N´m (225 in. lbs.).
Fig. 78 Retaining Pin Installed On Brake Pedal Pin (Typical)
1 - BRAKE PEDAL
2 - RETAINING CLIP
3 - BOOSTER INPUT ROD
Fig. 79 Vacuum Seal (Typical)
1 - MASTER CYLINDER ASSEMBLY
2 - VACUUM SEAL
5s - 50 BRAKESRS
POWER BRAKE BOOSTER (Continued)

(11) Connect wiring harness connector to brake
fluid level switch in the master cylinder fluid reser-
voir (Fig. 71). (12) If the vehicle is equipped with the 2.5L diesel
engine, install the coolant recovery pressure con-
tainer and bracket. (Refer t o 7 - COOLING/ENGINE/
COOLANT RECOVERY PRESS CONTAINER -
INSTALLATION) (13) If equipped with speed control, install speed
control servo and connect wiring connector. Tighten
the mounting nuts to a torque of 14 N´m (124 in.
lbs.). (14) Install the battery tray. Install the two nuts
and one bolt attaching the battery tray to the vehicle.
Tighten the bolt and nuts to a torque of 14 N´m (124
in. lbs.). (15) If vehicle is equipped with speed control, con-
nect the servo vacuum hose to the vacuum tank on
the battery tray. (16) Install the battery, clamp and mounting nut.
(17) Install the positive battery cable on the bat-
tery. (18) Install the negative battery cable on the bat-
tery. (19) Install the battery thermal guard shield.
CAUTION: Do not reuse the original brake lamp
switch. The switch can only be adjusted once. That
is during initial installation of the switch. If the
switch is not adjusted properly or has been
removed for some service, a new switch must be
installed and adjusted. (20) Remove and replace the brake lamp switch
with a NEW switch. (Refer t o 8 - ELECTRICAL/
LAMPS/LIGHTING - EXTERIOR/BRAKE LAMP
SWITCH - REMOVAL), (Refer t o 8 - ELECTRICAL/
LAMPS/LIGHTING - EXTERIOR/BRAKE LAMP
SWITCH - INSTALLATION) (21) Bleed the base brakes as necessary. (Refer to
5 - BRAKES - STANDARD PROCEDURE) (22) Road test vehicle to ensure proper operation
of the brakes.
PROPORTIONING VALVE
DESCRIPTION - PROPORTIONING VALVE
(HEIGHT SENSING)
NOTE: Only vehicles without antilock brakes (ABS)
have a proportioning valve. Vehicles with ABS uti-
lize electronic brake distribution which is controlled
through the ABS integrated control unit.
Vehicles not equipped with ABS use a height sens-
ing proportioning valve. It is mounted to the body of the vehicle above the rear axle (Fig. 80). It has an
actuator lever that attaches to the rear axle and
moves with the axle to help the valve sense the vehi-
cle height.
CAUTION: The height sensing proportioning valve
is not adjustable. No attempt should be made to
adjust it. It is replaced as a complete assembly.
CAUTION: The use of after-market load leveling or
load capacity increasing devices on this vehicle are
prohibited. Using air shock absorbers or helper
springs on this vehicle will cause the height sens-
ing proportioning valve to inappropriately reduce
the hydraulic pressure to the rear brakes. This inap-
propriate reduction in hydraulic pressure potentially
could result in increased stopping distance of the
vehicle.
OPERATION - PROPORTIONING VALVE
(HEIGHT SENSING)
Vehicles not equipped with ABS use a height sens-
ing proportioning valve. The height sensing proportioning valve operates
similarly to a standard proportioning valve in the fol-
lowing way. As hydraulic pressure is applied to the
valve, full input hydraulic pressure is supplied to the
rear brakes up to a certain pressure point, called the
split point. Beyond the split point, the proportioning
valve reduces the amount of hydraulic pressure to
the rear brakes according to a given ratio. Thus, on
light brake applications, approximately equal
hydraulic pressure will be transmitted to both the
front and rear brakes. Upon heavier brake applica-
tions, the hydraulic pressure transmitted to the rear
Fig. 80 HEIGHT SENSING PROPORTIONING VALVE
1 - PROPORTIONING VALVE
2 - ACTUATOR LEVER
3 - AXLE BRACKET
4 - REAR AXLE
RS BRAKES5s-51
POWER BRAKE BOOSTER (Continued)

COOLING
TABLE OF CONTENTS
page page
COOLING
DESCRIPTION
DESCRIPTION - COOLING SYSTEM........1
DESCRIPTION - HOSE CLAMPS...........1
OPERATION
OPERATION - COOLING SYSTEM.........2
OPERATION - HOSE CLAMPS............2
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - COOLING
SYSTEM LEAK TEST....................2
DIAGNOSIS AND TESTING - COOLING
SYSTEM FLOW CHECK.................3
DIAGNOSIS AND TESTING - COOLING
SYSTEM AERATION....................3
DIAGNOSIS AND TESTING - COOLING
SYSTEM DEAERATION..................4
STANDARD PROCEDURE
STANDARD PROCEDURE - COOLING
SYSTEM DRAINING....................4STANDARD PROCEDURE - COOLING
SYSTEM FILLING......................5
STANDARD PROCEDURE - ADDING
ADDITIONAL COOLANT.................5
STANDARD PROCEDURE - COOLANT
LEVEL CHECK........................5
SPECIFICATIONS
ACCESSORY DRIVE BELT TENSION.......5
TORQUE.............................5
SPECIAL TOOLS
COOLING SYSTEM.....................6
ACCESSORY DRIVE.......................7
ENGINE...............................13
TRANSMISSION.........................37
COOLING
DESCRIPTION
DESCRIPTION - COOLING SYSTEM
The cooling system components consist of a radia-
tor, electric fan motors, shroud, pressure cap, thermo-
stat, transmission oil cooler, water pump, hoses,
clamps, coolant, and a coolant reserve system to com-
plete the circuit.
DESCRIPTION - HOSE CLAMPS
The cooling system uses spring type hose clamps.
If a spring type clamp replacement is necessary,
replace with the original Mopartequipment spring
type clamp.
CAUTION: A number or letter is stamped into the
tongue of constant tension clamps. If replacement
is necessary, use only a original equipment clamp
with matching number or letter (Fig. 1).
Fig. 1 Spring Clamp Size Location
1 - SPRING CLAMP SIZE LOCATION
RSCOOLING7-1

OPERATION
OPERATION - COOLING SYSTEM
The engine cooling systems primary purpose is to
maintain engine temperature in a range that will
provide satisfactory engine performance and emission
levels under all expected driving conditions. It also
provides hot water (coolant) for heater performance
and cooling for automatic transmission oil. It does
this by transferring heat from engine metal to cool-
ant, moving this heated coolant to the radiator, and
then transferring this heat to the ambient air.
²When engine is cold: thermostat is closed, cool-
ing system has no flow through the radiator. The
coolant bypass flows through the engine only.
²When engine is warm: thermostat is open, cool-
ing system has bypass flow and coolant flow through
radiator.
Coolant flow circuits for the 2.4L and 3.3/3.8L
engines are shown in (Fig. 2).
OPERATION - HOSE CLAMPS
The spring type hose clamp applies constant ten-
sion on a hose connection. To remove a spring type
hose clamp, use Special Tool 6094 or equivalent, con-
stant tension clamp pliers (Fig. 3) to compress the
hose clamp.
DIAGNOSIS AND TESTING
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.
Fig. 2 Cooling System Flow
1 - HEATER - REAR (3.3/3.8L OPTIONAL EQUIPMENT) 6 - WATER PUMP
2 - HEATER - FRONT 7 - RADIATOR
3 - ENGINE 8 - COOLANT RECOVERY/RESERVE CONTAINER
4 - THERMOSTAT 9 - COOLANT FLOW - PRESSURE CAP VACUUM
5 - ENGINE OIL COOLER (3.3/3.8L OPTIONAL EQUIPMENT) 10 - COOLANT FLOW - PRESSURE CAP RELIEF
7 - 2 COOLINGRS
COOLING (Continued)

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 systemtester. 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.
DIAGNOSIS AND TESTING - COOLING SYSTEM
AERATION
Low coolant level in a cross flow radiator will
equalize in both tanks with engine off. With engine
at running and at operating temperature, the high
pressure inlet tank runs full and the low pressure
outlet tank drops, resulting in cooling system aera-
tion. Aeration will draw air into the water pump
resulting in the following:
²High reading shown on the temperature gauge.
²Loss of coolant flow through the heater core.
Fig. 3 Hose Clamp Tool
1 - HOSE CLAMP TOOL 6094
2 - HOSE CLAMP
Fig. 4 Pressure Testing
RSCOOLING7-3
COOLING (Continued)