Abnormal noise of wheel loader and forklift diesel engine——Piston pin

The main cause of the piston pin noise is the wear of the piston pin, connecting rod bushing or piston pin seat hole, resulting in too large fitting clearance, and the piston pin hits and makes a noise during movement.

The characteristics of the loaders piston pin noise are: the noise is more obvious when turning from idle speed to medium speed operation; the period (frequency) of the sound changes with the rise and fall of the engine speed. When the fuel injection time is advanced, the sound is more obvious and clear. After the front loader engine temperature rises, the noise is generally not weakened, and sometimes it is noticeably strengthened. Use the “cylinder-breaking method” test, the sound is weakened or disappeared.