GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

1

Did you review the Symptoms-Engine Cooling Diagnosis 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. Refer to Cooling System Draining and Filling .
  2. Perform a cooling system pressure test.

Is the repair complete?

System OK

Go to Step 5

5

Inspect for a stuck open, missing, or wrong type of thermostat. Refer to Thermostat Diagnosis .

Is the thermostat operating properly?

System OK

Go to Step 6

6

Install the correct replacement thermostat . Refer to one of the following procedures:

    • Caterpillar® 3126 Unit Repair Manual

Is the repair complete?

System OK

Go to Step 7

7

Run the engine in order to verify the repair.

Does the engine fail to reach normal operating temperature?

Go to Step 1

System OK