For 1990-2009 cars

#### Engine Fails To Reach Normal Operating Temperature

Possible Cause | Correction
--- | ---
DEFINITION: The engine fails to reach the normal operating temperature. Cool air is felt from the heater.
Coolant level or mixture incorrect. | Check the coolant mixture and add coolant as necessary.
Thermostat malfunction - stuck in the open position. | Inspect and replace the thermostat. Refer to Engine Coolant Thermostat Replacement .
Cooling system passages restricted |

1. Remove the obstruction.
2. Flush the cooling system as required.
3. Refill with coolant. Refer to Cooling System Draining and Filling .

Incorrect temperature gage reading | Check the temperature gage for proper operation. Connect a Scan Tool to the vehicle and read the system temperature. Compare this reading to the temperature gage. Replace the gage if necessary. Refer to Fuel/Temperature Gage Replacement .
Loss of system pressure Check the following areas for possible leakage:

• | Hoses

• | Coolant pump

• | Heater core

• | Thermostat housing

• | Radiator

• | Core plugs

• | Head gaskets

• | Intake manifold gaskets

Pressure check the system and cap. Ensure the correct cap is being used.