What Causes the Engine Noise After Shutting Off?
2 Answers
This is a normal phenomenon designed to prevent the engine from seizing due to rapid cooling after shutdown. Relevant explanations are as follows: 1. After driving for a period, various engine components reach high temperatures. Upon stopping, moving parts such as cylinders and piston rings, crankshafts and connecting rods may stick together due to excessive heat. This can cause tightness upon the next startup, commonly referred to as "cylinder seizure or bearing failure." 2. After prolonged driving, it's advisable to let the car idle for a few minutes before shutting off, allowing the engine temperature to decrease naturally. If the vehicle has an automatic cooling function, the fan will activate when the engine temperature is too high after shutdown, continuing to cool the engine until it reaches an appropriate temperature, at which point the fan will automatically turn off.
It's quite common for the engine to still make noise after turning off, mainly due to thermal expansion and contraction and the cooling system at work. The engine gets very hot during operation, and after parking, metal components like the exhaust manifold or turbocharger cool down and contract, producing ticking sounds. Additionally, the cooling fan might still be running because it's controlled by a thermostat and will continue to operate for a while to dissipate heat until the temperature drops to a safe level. If the fan runs for too long or the noise is unusually loud, it could be due to a faulty thermostat switch or insufficient coolant. In such cases, it's advisable to promptly check the fan system to prevent engine overheating damage. Regular maintenance includes periodically replacing the coolant and inspecting the fan belt. As someone who frequently works on cars, I’d say this is a minor issue, but delaying repairs can turn it into a major problem, affecting driving safety. It's best to use a diagnostic tool to check if the voltage is stable.
