There are all kinds of problems in using the car. For example, the engine may make a "dada" sound when the car is on, and the chassis will make a "PATA" sound when the car is off. People who don't know about the car often ask, is this a fault? In fact, these "fault phenomena" are not necessarily true faults, so we will talk about them briefly today.

When the engine starts cold, it makes a clattering sound

After the car is parked, the oil in the engine will flow back to the oil pan. When the engine is started, although there is oil in the oil passage, the effective oil pressure cannot be established at the first time. There is no effective oil film between the parts, especially there is a certain gap between the valve, rocker arm and hydraulic tappet, which results in the "clattering" sound when the engine is started. Of course, after the engine has been running for a period of time, the oil pressure is established, the oil film is formed, and the gap becomes smaller, and then the sound disappears. If there is still a clattering noise after driving for a long time, the owner should go to the repair shop for inspection.

What's the matter with the chassis snapping after flameout?

After the car stops at high speed, you will hear the sound of "popping" from the chassis. In fact, this is a normal phenomenon. After a long time driving, the temperature of the exhaust system will be very high, especially the three-way catalytic converter. Its working temperature will generally be 400-800 . After the car stops, the rapid cooling will cause the phenomenon of heat expansion and cold contraction, and then you will hear the sound of "Pa Pa Pa". The exhaust pipe is the same principle, so it's a normal phenomenon, so you don't need to worry about it.

For the two situations described above, I don't know if the car owners have ever encountered them?