Why does the engine still make noise after shutting down?
2 Answers
The reason why the engine still makes noise after shutting down is: when the engine temperature is too high, the radiator fan is still cooling and the muffler is also working. When the engine temperature is excessively high, the water temperature inside the engine does not drop immediately after the car is turned off, requiring the radiator fan to continue cooling. The cooling system will automatically activate to lower the engine system's temperature, and the fan will stop rotating once the appropriate water temperature is reached. During operation, the car burns gasoline, and through complex chemical reactions, part of the energy is converted into heat, which is expelled through the exhaust system. The muffler is essentially at the end of this system, functioning to reduce exhaust noise. While working, the muffler endures the impact of hot airflow, naturally heating up. After parking, due to thermal expansion and contraction, it produces noise.
Oh, after driving for so many years, I often encounter the engine making noises after shutting off. This is actually a normal phenomenon. The main reason is that the exhaust pipe and engine components are at high temperatures, and after shutting off, the metal starts to cool and contract, making crackling sounds, somewhat like a frying pan cooling down. Additionally, the fan might keep running for a while; it's helping the engine dissipate heat to prevent overheating damage. The fan is usually controlled by a temperature sensor and stops only when the temperature drops to a safe range. If the noise is very loud or there's a strange smell, then you should be careful—it might be loose components or a malfunction, and it's time to get it checked. After shutting off, try not to touch the hot parts to avoid burns; wait a while after parking, and the noise will stop. Don't worry about driving safety; it's just a daily physical change.
