Is the engine abnormal noise faulty?

There are various problems in 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. The car owners who don't know about the car often have questions. Is this a fault? In fact, these "fault phenomena" are not necessarily true faults. Today I will talk about them briefly.

The engine makes a clattering sound when it is cold started

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?

When the car stops at high speed, it will hear the sound of "Pa Pa Pa" 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 the sound of "Pa Pa Pa" will be heard. Exhaust pipe is the same principle, so this is a normal phenomenon, the owner does not need to worry.

Engine clattering, chassis clattering after flameout? What's going on?