What is the reason for the noise after parking the CRV?

[DanteRose]

It is caused by the thermal expansion and contraction of the engine, which is normal and nothing to worry about. Reason: When the engine is running, the temperature of each part is not the same. The cylinder block temperature generally does not exceed 100°C, while the exhaust pipe temperature is between 400~500°C, and the three-way catalytic converter temperature can even reach 600°C. Therefore, the expansion amounts of different parts vary. After the engine stops working, under the influence of the ambient temperature, it gradually cools down. The exhaust pipe and three-way catalytic converter, which are at higher temperatures, cool down faster and experience greater deformation, while the engine cylinder block cools down slightly slower. Due to the inconsistent deformation, friction occurs at the connection points, resulting in a "clicking" sound.