Piston knocking is a clear and rhythmic metal percussion sound, and its sound varies with temperature. The piston knocking is mainly due to the large gap between the cylinder wall and the piston of the northern Baotou Mercedes, and the noise caused by the collision between the piston and the cylinder wall in the piston movement.

The characteristics and judgment of the piston knocking.

(1) Baotou North Mercedes spare parts engine working noise is low when the noise is obvious, especially at idle speed when the noise is clearer (in addition to the oil port check). As the temperature rises, the noise decreases or disappears.

Secondly, the engine speed is fixed in the most sound position of the percussion sound, and the "broken fire" test of the cylinder is used in the cylinder. When a cylinder is "broken", the sound is obviously weakened or disappeared, that is, the cylinder is ringing. The side wall of the engine of the northern Baotou Mercedes Benz fittings can also be fitted to the side wall of the northern Mercedes Benz fittings on the side of the oil pipe, and the ears are attached to the end or the other end of the metal rod, for example, the sound of the vibrate knocking at a certain place, that is, the cylinder knocking for the cylinder.

(3) further judgment, the oil can be injected over the piston of a certain cylinder in a long mouth oil pot, rocking the engine a few cycles, and then starting the engine. At the moment of starting, if the sound is weakened or disappeared, the noise appears again soon, that is, the cylinder knocks.