What are the reasons for the abnormal noise after the Magotan is turned off?

[LaMicah]

There are 4 main reasons for the abnormal noise after the Magotan is turned off: 1. Uneven engine cooling: After turning off the engine, the temperature of various components decreases, and thermal expansion and contraction cannot occur at a completely uniform rate. This leads to friction between internal metal parts due to cooling contraction, resulting in abnormal noise. 2. Turbocharger cooling sound: Under normal conditions, exhaust gas temperatures can reach 600-700°C, accelerating friction heat from the rapidly rotating turbocharger. After shutdown, thermal expansion and contraction becomes very noticeable, producing abnormal noise. 3. Exhaust pipe cooling sound: During cold idling, the exhaust pipe can reach 200°C. With high vehicle load or when mixed gas burns in the exhaust pipe, temperatures become even higher. Thus, the exhaust pipe also produces noise from thermal expansion and contraction, often originating from the front end or flexible connection of the pipe. 4. Catalytic converter cooling sound: Normal operating temperature is 400-800°C. After shutdown, operation gradually stops and temperature decreases, causing thermal expansion and contraction of internal metal components that produces abnormal noise.