What Causes Abnormal Noises After the Car is Turned Off?

[LaJoel]

Here are the specific reasons for abnormal noises after the car is turned off: 1. Uneven engine cooling: After driving for a period of time, the engine temperature is very high. When turned off, the gaps between the metal components inside the engine cool and contract, causing friction and resulting in abnormal noises. 2. Turbocharger cooling: Under normal circumstances, the exhaust gas temperature reaches 600-700°C, accelerating the temperature generated by the rapid rotation and friction of the turbocharger. After turning off the engine, thermal expansion and contraction cause abnormal noises. 3. Exhaust pipe cooling: When the car is under high load or there is a mixture burning in the exhaust pipe, the exhaust pipe will also expand and contract due to heat, producing abnormal noises, which usually come from the front end of the exhaust pipe and the flexible connection points.