There are two faults 1. This sound is usually the sound of timing chain or valve clearance. (This is because when the chain stopper is pressed down, the gauge chain cam is deformed and the valve guide is excessively worn, resulting in abnormal and serious valve wear. ) 2. It is difficult to start the cold car, and the oil is cut off: the valve leaks, the cylinder is seriously worn, the carburetor is blocked, and the gasoline filter is blocked ...... 25919.20089.000000000606