Why does the engine make a buzzing sound after shutting down?
2 Answers
It is normal for a car to make a buzzing sound after shutting down. The sound may come from the turbocharger, or there may be abnormal noise when the automatic parking system intervenes during braking. Here are the detailed explanations: 1. After continuous high-speed rotation, the engine temperature will rise accordingly, causing the engine to become very hot and emit a buzzing sound. You can try not to shut off the engine immediately after stopping; wait for a while before turning it off. 2. The sound may come from the three-way catalytic converter. The operating temperature of the three-way catalytic converter is close to 1000 degrees Celsius, and the internal metal parts will expand and contract due to heat after shutting down. If none of the above situations apply, it may be a vehicle malfunction, and you should have it checked promptly.
I've been driving for over ten years, and it's quite common to hear a buzzing sound after turning off the engine, especially after driving on the highway or climbing hills in summer. This could be the engine cooling system still working, with the fan humming to help dissipate heat and prevent high temperatures from damaging internal components, such as turbocharger parts, which are prone to overheating. There's also the electronic control unit performing self-checks in the background, emitting alert sounds—nothing to worry about. Once, I encountered a situation where the fan ran for too long, and after checking, I found the coolant was low. Adding some fixed the issue. I recommend regularly inspecting the fan motor and wiring to avoid major problems in older cars. After long-distance driving, let the car rest for a while, and if the sound stops naturally, there's no need to rush to the repair shop and waste money.
