What Causes the Continuous Noise After the Car is Turned Off?
2 Answers
The continuous noise after the car is turned off is the sound of the fan operating. After the vehicle is turned off, if the engine temperature is high, the cooling system will automatically activate to cool down the engine, resulting in a continuous noise even after the car is turned off. This is a normal phenomenon. Once the engine system temperature drops, the cooling system will automatically stop working, typically within 3 to 5 minutes. How the Car Cooling Fan Works: Based on the principle of electromagnetic induction, the cooling fan uses a Hall sensor component as a synchronous detection device to control a set of circuits, switching the sequence of winding energization to generate a rotating magnetic field, achieving electronic commutation in a new type of electromechanical integrated fan. The cooling fan is installed between the engine and the radiator. When the fan blades rotate driven by the engine, they generate high-speed airflow, which carries away the heat from the coolant in the radiator, thereby cooling the engine. The Function of the Car Cooling Fan: The car cooling fan is mainly used to dissipate heat from the engine, ensuring that the engine does not malfunction due to high temperatures. The car engine must be adequately cooled in high-temperature working environments to maintain it at an optimal operating temperature, ensuring good engine performance, durability, and meeting exhaust emission requirements.
After driving for so many years, I've heard plenty of noises after turning off the engine. The most common is the sound of the exhaust pipe expanding and contracting due to heat, especially after driving on the highway. When the metal cools down, it makes a crackling sound, like popcorn popping, which is completely normal. Additionally, in turbocharged cars, the cooling system continues to work for a few minutes after shutdown, and the sound of the electric water pump and fan running is quite noticeable. There are also sounds like the cooling of the catalytic converter or the thermal deformation of the brake discs. However, if you hear something like a water leak or a sharp friction noise, you should be cautious, as it might indicate coolant backflow or mechanical component failure. Overall, don't stress too much—most of the time, it's just the car cooling down.
