What Causes High Engine Temperature at Idle Speed?
2 Answers
The reasons for high engine temperature at idle speed are: 1. Insufficient antifreeze in the engine cooling system; 2. Malfunction of the thermostat in the engine cooling system causing overheating; 3. Abnormal operation of the cooling fan in the engine cooling system, resulting in poor heat dissipation of the coolant; 4. Failure of the water pump in the engine cooling system, causing poor coolant circulation due to impaired pump rotation. Overheating, commonly known as "boiling over," can lead to deformation or even damage to the cylinder head and cylinder block. Precautions for high engine temperature include: 1. When driving, slow down and pull over, but do not rush to turn off the engine; 2. Never pour cold water on the engine to cool it down.
The car's water temperature is high at idle. I've encountered this several times myself, and there are quite a few possible causes. The most common issue is the cooling fan not working. At idle, engine heat tends to accumulate, and the fan is responsible for dissipating it—if it fails, it's a problem. Think about it: after starting the car, wait a few minutes and check if the fan is spinning. If not, it might be due to motor aging or poor wiring contact. Additionally, if the thermostat is stuck closed, the coolant won't circulate outside the engine, especially at idle when cooling is already poor, leading to overheating. You should also check for insufficient or leaking coolant—open the radiator cap and see if the level is below the standard mark. If the water pump is leaking or the belt is loose, insufficient coolant circulation will naturally cause the water temperature to spike. If this happens, don’t panic. Immediately stop the car, turn off the engine, and open the hood to let heat escape—this prevents cylinder damage. Then, take it to a mechanic to check these points to avoid turning a small issue into a big one.
