Preliminary Diagnosis
- Does overheating occur while pulling a trailer?
- Is overheating occurring after prolonged idle in gear, A/C system operating?
- Is overheating occurring after prolonged driving in slow city traffic, traffic jams, parades, etc.?
Is the trailer within the recommended towing weight?
If none of the above apply refer to the chart below.
Possible Cause | Correction |
|---|---|
Coolant fan inoperative | Inspect the circuit. |
Thermostat stuck in closed position | 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 (especially 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 using the J 24460-01 with the J 24460-92 . Ensure the correct cap is being used. |
Loose, damaged and or missing air seals or deflector | Repair or replace as required. |
Cooling system passages blocked | Remove the obstruction. Flush the cooling system as required and refill with coolant. |
Malfunctioning coolant pump (eroded or broken impeller blades) | Replace the coolant pump. |
Air trapped in cooling system | Refill the cooling system. |
- Verify that the cooling system is properly filled.
- If the complaint is a low 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 gauge or switch if necessary.
- If the complaint is no heat from the HVAC system, refer to Heating Insufficient in HVAC System with A/C - Manual.
- Verify the proper operation of the thermostat. Refer to Thermostat Diagnosis
