GM Service Manual Online
For 1990-2009 cars only

Engine Overheats

Cause

Correction

Loss of system pressure

Perform the radiator cap pressure test.

Loss of coolant

Add coolant. Refer to Maintenance and Lubrication.

Weak coolant solution

Perform a coolant solution test for a proper 50/50 mixture.

Coolant pump drive belt loose or missing

Adjust or replace the belt.

Dirt, leaves or insects on the front of the radiator

Clean the front of the radiator.

Hoses, coolant pump, heater, thermostat housing, radiator, core plugs, or head gasket leakage

Repair the respective parts as necessary.

Faulty thermostat

Check the thermostat.

Ignition timing retarded

Set the timing. Refer to Timing in Driveability and Emissions.

Faulty electric cooling system

Inspect the electric cooling system. Refer to Electrical Cooling System in Electrical Diagnosis.

Plugged or rotted radiator hoses

Replace the hoses.

Faulty coolant pump

Replace the coolant pump.

Plugged radiator, faulty cap

Check the radiator.

Cracked or plugged cylinder head or block

Repair the cylinder head or block as necessary.