What Causes Engine Overheating Warning?
3 Answers
Engine overheating warning can be caused by the following reasons: Coolant Leakage or Insufficient Coolant: A coolant system leak leads to insufficient antifreeze, which in turn causes the antifreeze temperature to rise. If the antifreeze level is found to be low, the first step should be to check for leaks. Cooling Fan Malfunction: A faulty cooling fan prevents timely heat dissipation from the antifreeze when the car engine operates at medium to high speeds, causing the antifreeze temperature to rise and leading to issues like "boiling over". Water Pump Failure: When the water pump fails, the water on the engine's heat conduction side cannot circulate promptly, resulting in a rapid rise in water temperature after the engine starts.
I've been driving for over a decade and have seen the temperature warning light come on several times – this is no small matter. Common causes include radiator leaks, water pump failure, insufficient coolant, and an often-overlooked stuck thermostat that can cause engine temperature to skyrocket. The worst thing is continuing to drive after overheating, which can easily lead to cylinder scoring and engine failure. Once when driving on mountain roads, the warning suddenly came on – I immediately turned off the AC, turned on the heater to help dissipate heat, and pulled over to check. Turned out there was a small crack in a radiator hose and all the coolant had leaked out. In such situations, stop immediately to check the overflow tank level – never add cold water, wait until the engine cools completely before refilling with proper coolant. If the dashboard warning light is flashing red, don't force it – call for roadside assistance.
When repairing cars, engine overheating is often related to the water circulation system. It could be due to a blown fuse in the electric fan causing it to stop, or a clogged radiator with debris leading to poor heat dissipation. Last summer, I worked on a Tiguan where the owner had recklessly topped up with tap water, leaving the radiator full of scale. Another common issue is corrosion of the water pump impeller, which completely disrupts water circulation. I've disassembled several overheated engines where the pistons were stuck to the cylinder walls, making overhauls particularly challenging. It's advisable to keep a bottle of distilled water in the car for emergencies—use only this when adding water. Regular maintenance should also include monitoring the coolant color; replace it if it turns cloudy. Prolonged overheating can also damage the transmission.
