GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Check the level of the coolant in the surge tank.

Is the coolant at the proper level?

--

Go to Step 3

Go to Step 2

2

Add engine coolant as necessary.

Does the engine still fail to reach normal operating temperature?

--

Go to Step 3

System OK

3

Check to see if the correct type of thermostat was installed, or if the thermostat sticks (or is stuck) in the open position.

Was the incorrect thermostat installed or does the thermostat stick, or is the thermostat stuck, in the open position?

--

Go to Step 4

System OK

4

Replace the thermostat. Refer to Engine Coolant Thermostat Replacement .

Does the engine still fail to reach normal operating temperature?

--

--

System OK