Why is there a ticking sound after the engine shuts off?

[JesseAnn]

This is a normal sound caused by the thermal expansion and contraction of the engine. The reasons and solutions for the ticking sound after the engine shuts off are as follows: 1. Uneven cooling of the engine: After driving for a while, the engine temperature is very high. After shutting off, the temperature of various components decreases unevenly, and the thermal expansion and contraction cannot be exactly the same, which will cause friction between the metal components inside the engine and produce abnormal sounds. Solution: Do not turn off the engine immediately after parking. 2. Exhaust pipe, three-way catalytic converter, and turbo cooling: After shutting off, the high-temperature exhaust pipe and three-way catalytic converter cool down faster, deform more significantly, and exhibit noticeable thermal expansion and contraction, resulting in abnormal sounds. (Normal phenomenon, no solution available)