Mitsubishi Galant (2004+). Manual - part 1651

SPECIAL TOOL

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ENGINE COOLING

14-3

SPECIAL TOOL

M1141000600279

ENGINE COOLING DIAGNOSIS

INTRODUCTION

M1141005300347

The system cools the engine so that it does not over-
heat and maintains the engine at an optimum tem-
perature. 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

M1141005200340

Use these steps to plan your diagnostic strategy. If 
you follow them carefully, you will be sure to find 
most of the engine cooling faults.
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

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TOOL

TOOL NUMBER AND 
NAME

SUPERSESSION

APPLICATION

MB991871
LLC changer

General service tool

Coolant refilling

MB991871

SYMPTOM

INSPECTION 
PROCEDURE

REFERENCE 
PAGE

Coolant Leak

1

P.14-4

Engine Overheating

2

P.14-5

ENGINE COOLING DIAGNOSIS

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ENGINE COOLING

14-4

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.

• When installing and removing the tester and when test-

ing, be careful not to deform the filler neck of the radia-
tor.

Check that the coolant level is up to the filler neck. Install a radi-
ator 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 

Step 2.

NO :  There is no action to be taken.

STEP 2. Retest the system.
Q: It there still coolant leakage?

YES : Return to Step 1.
NO :  The procedure is complete.

ACX01844 AB

CAP ADAPTER

ADAPTER

ENGINE COOLING DIAGNOSIS

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ENGINE COOLING

14-5

INSPECTION PROCEDURE 2: Engine Overheating

DIAGNOSIS

STEP 1. Remove the radiator cap and check for coolant 
contamination.
Q: Is the coolant contaminated with rust and oil?

YES : Replace it. Refer to 

P.14-7

.

NO :  There is no action to be taken. Go to Step 2.

STEP 2. Check the radiator cap valve opening pressure.
NOTE:  Be sure that the cap is clean before testing. 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: 83 kPa (12 psi)
Standard value: 93 

− 123 kPa (14 − 18 psi)

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

YES : Go to Step 3.
NO :  Replace the radiator cap. Then go to Step 5.

STEP 3. Check thermostat operation.

Refer to 

P.14-18

.

Q: Does the thermostat operate correctly?

YES : Go to Step 4.
NO :  Replace the thermostat, then go to Step 5.

STEP 4. Check the drive belt for slippage or damage.

Refer to GROUP 00, Maintenance Service 

− Drive Belts 

(Check Condition). <2.4L Engine>

P.00-43

 , <3.8L 

Engine>

P.00-43

 .

Q: Is the drive belt loose or damaged?

YES : Adjust or replace the drive belt, then go to Step 5.
NO :  There is no action to be taken.

STEP 5. Retest the system.

Check the engine coolant temperature.
Q: Is the engine coolant temperature abnormally high?

YES : Return to Step 2.
NO :  The procedure is complete.

ACX01845 AB

CAP ADAPTER

ON-VEHICLE SERVICE

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ENGINE COOLING

14-6

ON-VEHICLE SERVICE

ENGINE COOLANT LEAK CHECK

M1141001000333

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 taken out, be careful not to spill any 

coolant.

• Be careful when installing and removing the tester and 

when testing not to deform the filler neck of the radia-
tor.

1. Check that the coolant level is up to the filler neck. Install a 

radiator tester and apply 160 kPa (23 psi) pressure, and 
then check for leakage from the radiator hose or 
connections.

2. If there is leakage, repair or replace the appropriate part.

RADIATOR CAP PRESSURE CHECK

M1141001300419

NOTE: Be sure that the cap is clean before testing. 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 indicator of the gauge stops 

moving.

Minimum limit: 83 kPa (12 psi)
Standard value: 93 

− 123 kPa (14 − 18 psi)

3. Replace the radiator cap if the reading does not remain at or 

above the limit.

ACX01844 AB

CAP ADAPTER

ADAPTER

ACX01845 AB

CAP ADAPTER