GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value

Yes

No

1

Check the coolant level.

Is the coolant level below the add mark?

--

Go to Step 2

Go to Step 3

2

  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

--

3

Check for a stuck open, missing, or wrong type of coolant thermostat.

Is the thermostat operating properly?

--

System OK

Go to Step 4

4

Install the correct replacement thermostat.

Is the repair complete?

--

System OK

--