Should You Turn Off the Engine When the Water Temperature is High?
3 Answers
Whether to turn off the engine when the water temperature is high depends on the specific situation. If the coolant can still circulate normally, it is recommended not to turn off the engine, as shutting it down would prevent the coolant from cooling. If the coolant can no longer circulate properly, it is advisable to turn off the engine, as continuing to run it would not cool the coolant and could further raise its temperature. When the engine temperature is too high, it is best to find a safe place to park and open the hood to help dissipate heat. Coolant needs to be replaced regularly. If not changed for a long time, the freezing point of the coolant may rise while the boiling point may drop, which can affect the engine's normal operation. It is recommended to replace the coolant every two years.
As someone who frequently drives long distances, I immediately become alert whenever I see the temperature gauge climbing rapidly. Under no circumstances should you turn off the engine directly in this situation! If the engine stops abruptly at high temperatures, the coolant in the radiator stops circulating, but the internal metal components are still hot, trapping the heat inside and preventing it from dissipating. Last month, I witnessed a car in the neighboring workshop whose cylinder head warped due to this, and the repair costs were nearly half the price of a new engine. I remember once when I was driving my old Passat up a winding mountain road, the temperature needle suddenly shot up to the red line. I immediately shifted to neutral and revved the engine. Only after the RPM increased and the fans kicked in at full speed did the needle gradually drop back down. The key is to first find a safe spot to pull over slowly, then let the engine idle for two to three minutes before turning off the ignition.
I've learned a lot from my friend's auto repair shop where such issues are common. Immediately turning off the engine when it overheats can actually worsen the problem because the water pump stops, halting coolant circulation while the engine remains hot like a glowing iron block. Once, I helped a neighbor in a similar situation: first, turn the heater to maximum to assist cooling (though it gets uncomfortably hot), and after stopping on level ground, never open the radiator cap immediately—scalding coolant can spray out and cause burns. A handy trick is to slowly unscrew the cap wrapped in a wet towel, waiting until the hissing stops before adding cold water. However, newer cars now come with automatic cooling fans that continue running for a while after engine shutdown.
