The main reasons for the abnormal noise of the Copeland DLF piston are as follows:

(1) The Copeland DLF piston and the connecting rod bushing are worn too much, and the coordination is severely loosened. The main reason is poor lubrication. There is no oil hole on the engine connecting rod. The Copeland DLF piston and bushing are lubricated by the lubricating nozzle. The oil pan is sprayed upward. If the oil pressure is too low and the oil injection is not good, it will cause poor lubrication of the piston pin and connecting rod bushing. Poor oil injection and poor piston cooling will also aggravate the wear of the piston pin and connecting rod bushing. If the engine oil deteriorates or becomes thinner, it will also cause increased wear. Therefore, we must pay attention to the quality of the oil. It is recommended to replace the oil and oil filter regularly.

(2) When repairing the connecting rod bushing, the size positioning is not accurate, the bushing and the connecting rod are not properly matched, and abnormal noise of the piston pin may occur. When repairing, the connecting rod bushing must be installed according to the standard so that it can be pressed in under a certain pressure.

After the abnormal sound of the Copeland DLF piston occurs, different measures can be taken according to its severity:

　　(1) If the abnormal noise of the Copeland DLF piston is slight, you can continue driving; but if there are maintenance conditions, it is recommended to replace it.

　　(2) If the abnormal noise of the Copeland DLF piston is severe (the abnormal noise is obvious when running at high speed and normal temperature), it should be repaired and replaced immediately.

　　(3) The replacement of Copeland DLF piston and connecting rod bushing must be carried out in strict accordance with the standard, and the clearance fit must be correct.