Verify that overheating is not caused by the following conditions:
- While pulling a trailer that is within the recommended towing weight.
- After prolonged idle in gear, with the A/C system operating.
- 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.
- Verify that the cooling system is properly filled.
- 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.
- Compare this reading to the temperature gauge.
- Replace the gauge or switch if necessary.
- If the complaint is no heat from the HVAC system. Verify the proper operation of the thermostat. Refer to Thermostat Diagnosis .
Possible Causes
Possible Cause | Correction |
|---|---|
Coolant fan inoperative | Refer to Low Engine Coolant Indicator Always On . |
Thermostat stuck closed | Replace the thermostat |
Radiator fins obstructed | Remove or relocate add-on parts that block air to the radiator. Clean away bugs, leaves, etc. In cold climates, clear away snow, etc. from the radiator core. |
Surge tank outlet hose pinched or kinked (at radiator) | Relieve kinks by re-routing. Replace the hose if necessary. |
Incorrect radiator | Check the radiator usage chart in a parts catalog. If needed, replace with the correct radiator. |
Loss of system pressure | Pressure check system and surge tank cap. Ensure the correct cap is being used. |
Damaged or missing air seals or deflector | Repair or replace as required. |
Malfunctioning coolant pump | Replace the coolant pump. |
Air trapped in cooling system | refill the cooling system |
