Weichai 250KW generator pumps fuel pump assembly turbocharged engine 40.10. It has traveled more than 300,000 kilometers, during which more than 200,000 kilometers in conducted a major overhaul. Some time ago due to burning oil and overhaul intervals thereafter engine working and traveling more than 10,000 kilometers. In a moving way, the driver feels that the engine power drop and abnormal noise, continue driving the situation to deteriorate until the engine is stopped. Towed dismantling the repair shop for the first 3-cylinder piston melt the top (area 2/3) after catching. [Troubleshooting] First, carefully looked at the top of the molten piston. The cylinder has been strained cylinder, piston rings and piston ring grooves also stick together. By observing stars, cylinder and piston and piston ring grooves strain adhesion is due to melting caused by the piston crown. Therefore, the friction heat exclude improper assembly or by the mechanical part of the choice of materials and lead to the possibility of discomfort caused by melting the top of the piston, but also ruled out by examining the factors that caused the engine temperature is too high and melt the top. And to provide a detailed understanding of parts manufacturers, the exclusion of the parts itself. So, the question arises in there?