GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

1

Check the level of the coolant in the coolant surge tank.

Is the coolant in the surge tank at the proper level?

Go to Step 3

Go to Step 2

2

Add engine coolant as necessary. Refer to Cooling System Draining and Filling .

Does the engine still fail to reach normal operating temperature?

Go to Step 3

System OK

3

Check if the thermostat is stuck open.

Is the thermostat stuck in the open position?

Go to Step 5

Go to Step 4

4

Check to see if the correct type of thermostat was installed.

Was the incorrect thermostat installed?

Go to Step 5

System OK

5

Replace the thermostat. Refer to Engine Coolant Thermostat Replacement .

Does the engine still fail to reach normal operating temperature?

--

System OK