For 1990-2009 cars

## Engine Overheating Preliminary Diagnosis

Verify that overheating is not caused by the following conditions:

1. While pulling a trailer that is within the recommended towing weight.
2. After prolonged idle in gear, with the A/C system operating.
3. After prolonged driving in slow city traffic, traffic jams, parades, etc.

If these conditions can be eliminated as the cause of overheating, refer to the table below.

1. Verify that the cooling system is properly filled.
2. If the complaint is a low temperature gauge reading, check the temperature gauge for proper operation. Connect a Scan Tool to the vehicle and read the system temperature.
3. Compare this reading to the temperature gauge.
4. Replace the gauge or switch if necessary.
5. If the complaint is no heat from the HVAC system, refer to HVAC System Check in HVAC Systems - Manual.
6. Verify the proper operation of the thermostat. Refer to Thermostat Diagnosis .