GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

DEFINITION: The engine fails to reach the normal operating temperature. Cool air is felt from the heater.

1

Check the thermostat.

Is the thermostat stuck open or was the wrong type of thermostat previously installed?

--

Install a new thermostat of the correct type and heat range.

Go to Step 2.

2

Check the coolant level.

Is the coolant level below the ADD mark?

--

Add coolant.

Go to Step 3.

3

Inspect the radiator.

Is the radiator plugged or is there a faulty cap?

--

Check the radiator or the cap.

Go to Step 4.

4

Inspect the cylinder head.

Is the cylinder head or block cracked or plugged?

--

Repair the cylinder head or block as necessary.

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