Engine Coolant Temperature - High

The engine's coolant temperature is measured by a sensor. If the temperature rises too high, it could mean the engine is at risk of overheating, which can cause serious damage.

The Engine Control Module (ECM) sees a coolant temperature reading that exceeds the normal operating range, typically above 230°F (110°C).

Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.

1. 11. Check the coolant level in the reservoir. Fill if low and monitor for leaks.
2. 22. Inspect the coolant temperature sensor connector and wiring for damage or corrosion. Repair as necessary.
3. 33. Use a scan tool to read the current coolant temperature; compare it to the value from the sensor. If they differ significantly, suspect a bad sensor.
4. 44. Start the engine and let it reach operating temperature. Observe if the thermostat opens. Feel the upper radiator hose—if it's hot and the hose remains cool, the thermostat may be stuck.
5. 55. If both the sensor and thermostat test good, check the water pump operation—look for leaks or signs of cavitation.
6. 66. If all previous checks are normal, consider potential issues with the engine's internal components or additional obstructions in the cooling system.

• Low coolant level
• Faulty coolant temperature sensor
• Thermostat stuck closed
• Radiator blockage
• Failed water pump

$$$