Coolant Temperature Warning / Engine Overheating

How to Fix It

1. Stop and switch off the engine.

   Pull over and turn off the engine immediately when the temperature warning appears. Using the cabin heater at maximum can briefly draw heat from the engine as you reach a safe stop. Do not continue driving — cylinder head warping begins within minutes of severe overheating.

2. Wait 30 minutes before touching the cooling system.

   Mitsubishi cooling systems are pressurized — releasing the coolant cap while the engine is hot causes scalding steam. Wait at least 30 minutes with the hood open before approaching the coolant reservoir. Cover the cap with a thick cloth and turn slowly to release pressure.

3. Check the coolant level.

   After cooling, check the coolant reservoir (translucent tank with MIN/MAX markings) level. Mitsubishi engines typically use a Long-Life Coolant (LLC) — blue or pink depending on the model; do not mix types. If the level is repeatedly low, find and repair the leak.

4. Check the radiator fan.

   With the engine at operating temperature, the electric fan should be running. If it is not spinning, check the fan relay and fuse in the engine bay fuse box. A failed fan relay is an inexpensive part and a common cause of overheating in slow traffic.

5. Check the thermostat and water pump.

   A thermostat stuck closed causes overheating within minutes even with adequate coolant. If the lower radiator hose stays cold while the engine overheats, the thermostat is not opening. Listen for a whining or rumbling from the front of the engine — this can indicate a failing water pump bearing.