Mitsubishi Galant. Manual — part 331

GENERAL INFORMATION

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ENGINE COOLING

14-2

.

G EN ER A L IN FO R M ATIO N

M1141000100070

The cooling system is designed to keep every part of
the engine at appropriate temperature in whatever
condition the engine may be operated. The cooling
method is of the water-cooled, pressure forced
circulation type in which the water pump pressurizes
coolant and circulates it throughout the engine. If the
coolant temperature exceeds the prescribed
temperature, the thermostat opens to circulate the
coolant through the radiator as well so that the heat
absorbed by the coolant may be radiated into the air.

The water pump is of the centrifugal type and is
driven by the drive belt from the crankshaft. The
radiator is the corrugated fin, down flow type and is
cooled by an electrical radiator fan. And if the engine
coolant temperature reaches 110

°

C(230

°

F) or

higher, the radiator fan control rotates the radiator
fan for up to 5 minutes even after the ignition switch
is turned to the "LOCK (OFF)" position [the fan stops
its rotation when the engine coolant temperature
decreases to 110

°

C(230

°

F) or lower.]

CONSTRUCTION DIAGRAM

EN G IN E C O O LIN G D IA G N O SIS

INTRODUCTION

M1141005300091

The system cools the engine so that it does not
overheat and maintains the engine at an optimum
temperature. The system components are the
radiator, water pump, thermostat, condenser fan
assembly. Possible faults include low coolant,
contamination, belt loosening and component
damage.

TROUBLESHOOTING STRATEGY

M1141005200094

Use these steps to plan your diagnostic strategy. If
you follow them carefully, you will be sure that you

have exhausted most of the possible ways to find an
engine cooling fault.

AC004034 AB

A/T OIL COOLER HOSE

RESERVE TANK

LOWER INSULATOR

RADIATOR

RADIATOR SUPPORT

ENGINE COOLING DIAGNOSIS

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ENGINE COOLING

14-3

1. Gather information from the customer.

2. Verify that the condition described by the

customer exists.

3. Find and repair the malfunction by following the

SYMPTOM CHART.

4. Verify that the malfunction is eliminated.

SYMPTOM CHART

M1141005600069

SYMPTOM PROCEDURES

INSPECTION PROCEDURE 1: Coolant Leak

DIAGNOSIS

STEP 1. Check for coolant leaks.

WARNING

When pressure testing the cooling system, slowly
release cooling system pressure to avoid getting
burned by hot coolant.

CAUTION

•

Be sure to completely clean away any moisture from
the places checked.

•

When the tester is removed, be careful not to spill any
coolant from it.

•

When installing and removing the tester and when
testing, be careful not to deform the filler neck of the
radiator.

Check that the coolant level is up to the filler neck. Install a
radiator cap tester and apply 160 kPa (23 psi) pressure, and
then check for leakage from the radiator hose or connections.

Q: Is leakage present from the radiator hose or

connections?
YES : Repair or replace the appropriate part, then go to

Step2.

NO : There is no action to be taken.

SYMPTOMS

INSPECTION
PROCEDURE

REFERENCE
PAGE

Coolant leak

1

P.14-3

.

Engine overheating

2

P.14-4

.

Radiator fan and condenser fan do not operate

3

P.14-5

.

Radiator fan and condenser fan do not change speed or stop

4

P.14-10

.

Radiator fan does not operate

5

P.14-12

.

Condenser fan does not operate

6

P.14-13

.

ACX01844 AB

CAP ADAPTER

ADAPTER

ENGINE COOLING DIAGNOSIS

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ENGINE COOLING

14-4

STEP 2. Check trouble symptoms.

Q: Is the trouble symptom reproduced?

YES : Return to Step 1.
NO : This diagnosis is complete.

INSPECTION PROCEDURE 2: Engine Overheating

DIAGNOSIS

STEP 1. Check for coolant contamination.

Q: Is the coolant contaminated?

YES : Replace it. Refer to GROUP 00, Maintenance

Service-Engine Coolant (Change)

P.00-50

.

NO : There is no action to be taken, then go to Step 2.

STEP 2. Check symptoms.

Q: Is the radiator clogged?

YES : Return to Step 1.
NO : Go to Step 3.

STEP 3. Check the radiator cap valve opening pressure.

NOTE: Be sure that the cap is clean before testing, since rust
or other foreign material on the cap seal will cause an improper
reading.
(1) Use a cap adapter to attach the cap to the tester.
(2) Increase the pressure until the gauge indicator stops

moving.

Minimum limit: 64 kPa (9.2 psi)

Standard value: 73

−−−−

103 kPa (11

−−−−

15 psi)

Q: Does the reading remain at or above the minimum limit?

YES : Go to Step 4.
NO : Replace the radiator cap.Then go to Step 6.

STEP 4. Check thermostat operation.
Refer to

P.14-19

.

Q: Does the thermostat operating correctly?

YES : Go to Step 5.
NO : Replace the thermostat, then go to Step 6.

STEP 5. Check the drive belt for loosening or damage.
Refer to GROUP 00, Maintenance Service

−

Drive Belts

(Check Condition)

P.00-39

.

Q: Is the drive belt loose or damaged?

YES : Adjust or replace the drive belt, then go to Step 6.
NO : There is no action to be taken.

ACX01845 AB

CAP ADAPTER

ENGINE COOLING DIAGNOSIS

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ENGINE COOLING

14-5

STEP 6. Check trouble symptoms.

Q: Is the coolant temperature abnormally high?

YES : Return to Step 3.
NO : This diagnosis is complete.

INSPECTION PROCEDURE 3: Radiator Fan and Condenser Can do not Operate

AC004035

Radiator Fan and Condenser Fan Drive Circuit

AB

AC000242

FUSIBLE LINK (4) AND
CONNECTORS: A-13X,A-21X

FUSIBLE
LINK (4)

BATTERY

A-21X

A-13X

AB

AC000260AB

CONDENSER FAN
MOTOR CONNECTOR
AND CONNECTOR: A-30

CONDENSER
FAN MOTOR
CONNECTOR

A-30

RADIATOR
FAN