There are two main reasons for the problem of excessive heating in plunger pumps. The first reason is the frictional heat generated by the friction of machine components. Due to the dry or semi dry friction state of the moving surface, friction between components generates heat. The second reason is the heat generated by the friction of the liquid. When high-pressure oil leaks from various clearances into the low-pressure chamber, a large amount of hydraulic energy is lost and converted into thermal energy. Therefore, by selecting appropriate mechanical component clearances, fuel tank capacity, and cooling systems, problems of pump overheating and high oil temperature can be avoided. In addition, clogging of the return oil filter can lead to excessive back pressure of the return oil, as well as problems such as high oil temperature and overheating of the pump body.The plunger pump still has the problem of oil leakage, and the main reasons are as follows:The main shaft oil seal is damaged or the shaft has defects or scratches.Excessive internal leakage leads to an increase in pressure at the seal, resulting in seal damage or displacement.Due to the use of excessively long and narrow oil drain pipes, oil leakage occurred at the pump body seal.The external oil pipe of the pump is loose, damaged, the sealing gasket is aging or cracked, which leads to oil leakage at the sealing part of the pump body.Loose bolts in the variable adjustment mechanism resulted in damage to the pump body seal.The cast iron pump casing has quality issues such as sand holes or poor welding.