Mitsubishi Eclipse. Manual — part 650

ENGINE COOLING DIAGNOSIS

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COOLING SYSTEM

14-3

ENGINE COOLING DIAGNOSIS

INTRODUCTION

M1141005300217

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

M1141005200210

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

M1141005600207

SYMPTOMS

INSPECTION
PROCEDURE

REFERENCE
PAGE

Coolant Leak

1

P.14-4

Engine Overheating

2

P.14-4

Radiator Fan and Condenser Fan do not Operate

3

P.14-6

Radiator Fan and Condenser Fan do not Change Speed or Stop

4

P.14-14

Radiator Fan does not Operate

5

P.14-16

Condenser Fan does not Operate

6

P.14-17

ENGINE COOLING DIAGNOSIS

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COOLING SYSTEM

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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 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. Check symptoms.
Q: Can the symptom be reproduced?

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

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 GROUP 00, Maintenance Service

− Engine Coolant (Change)

P.00-58

.

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

ACX01844 AB

CAP ADAPTER

ADAPTER

ENGINE COOLING DIAGNOSIS

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COOLING SYSTEM

14-5

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.14-24

.

Q: Is 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)

P.00-46

.

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. Check symptoms.
Check the coolant temperature gauge.
Q: Is the coolant temperature abnormally high?

YES : Return to Step 2.
NO : This diagnosis is complete.

ACX01845 AB

CAP ADAPTER

ENGINE COOLING DIAGNOSIS

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COOLING SYSTEM

14-6

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

AC102870

Radiator Fan and Condenser Driver Circuit

<2.4L ENGINE>

AB