Failure sometimes occurs; soon after starting, the engine will produce "tick" sound, which will disappear gradually as the engine temperature increases. In most cases, the noise will disappear after 5 min, but the noise will not disappear after warming up. The reason for the fault is that the piston pin part is emitted during the operation of the engine. According to the usual design tolerance, the piston pin hole is produced at the maximum tolerance, and the piston pin is produced at minimum tolerance, so noise can be generated. In general, the noise is minimal and does not affect the reliability or life of the engine. The method of solving the piston and piston pin chatter is to replace the 6 piston rings with a piston pin, and the new piston assembly will have a smaller gap between the piston and the piston pin, which is different from the piston model and the noise strength is not lost. Normally, when the engine is running at idle speed, the noise of the piston and the piston pin can be heard, and the type of piston is different if it is carefully tilting. The noise intensity is also different from the "ticking" sound that only the piston parts of the 1 cylinders give out noise, and if there is a "click" sound, it is indicated that not only the piston of the 1 cylinders has made a noise, but the following steps should be checked. (1) on the W car, it is necessary to ensure that the right fender of the engine does not interfere with the balance block of the engine crankshaft. This usually happens in cold weather, which is because the fender is easy to bend. (2) check whether the diameter of the cylinder and the diameter of the piston meet the standards. Too much clearance between the cylinder wall and the piston will also cause noise. In this case, it is necessary to replace the piston. When installing the new piston and the piston pin assembly on the connecting rod, be careful not to damage the piston pin or the piston pin hole, otherwise the noise will occur because of the excessive wear and the excessive clearance.