Why does the car sometimes have fan noise after being parked for a day?
2 Answers
It is normal for the engine fan to operate after parking and turning off the engine. Here are the specific explanations: Reason: The automatic activation of the engine fan is due to the engine overheating after prolonged operation. The computer system detects this and initiates cooling to prevent the engine from cooling too rapidly after shutdown, which could lead to "seizure" and engine failure. Engine seizure: After driving for a period, various engine components reach high temperatures. If the car is parked immediately, parts like the cylinders and piston rings, crankshaft and connecting rods may "stick" together due to the high temperature. This can cause tightness upon the next startup, commonly referred to as "cylinder seizure or bearing seizure."
I've been driving for decades, and this situation is quite common. The fan noise after parking is mostly the engine cooling fan running, because after the car has been parked for a day, the internal temperature is still relatively high, and the system will automatically activate the fan to dissipate the residual heat. Especially in hot weather, if the car is parked in the sun, the temperature sensor will detect the high temperature and activate the fan. It could also be related to the air conditioning system—if you had the AC on before parking, the fan might sometimes delay shutting off to regulate the cabin temperature. However, if the fan noise suddenly becomes very loud, lasts for a long time, or is accompanied by a strange smell, you should be cautious. It might indicate aging wiring, a faulty relay, or unstable battery voltage, which could affect the normal operation of the electrical system. I recommend paying attention to the frequency of the noise. If it doesn’t happen often, it’s likely just normal cooling behavior. But for safety, have a mechanic check the sensors and fuses during your next maintenance service.
