GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

1

Did you review the Symptoms - Engine Cooling diagnostic information and perform the necessary inspections?

Go to Step 2

Go to Symptoms - Engine Cooling

2

Verify that the engine does not reach normal operating temperature.

Does the engine reach normal operating temperature?

System OK

Go to Step 3

3

Inspect the coolant level.

Is the coolant level below the add mark?

Go to Step 4

Go to Step 5

4

  1. Add coolant as necessary.
  2. Perform a cooling system pressure test.

Does the cooling system hold pressure?

System OK

Go to Step 5

5

Inspect for a stuck open, missing, or incorrect thermostat. Refer to Thermostat Diagnosis .

Is the thermostat operating properly?

System OK

Go to Step 6

6

Install the correct replacement thermostat. Refer to Engine Coolant Thermostat Housing Replacement .

Is the repair complete?

Go to Step 7

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7

Run the engine in order to verify the repair.

Does the engine fail to reach normal operating temperature?

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System OK