Overheating fault occurs at the friction points between crankshaft and bearing, crosshead and sliding plate, packing and piston rod, etc. The temperature exceeds the specified value, which is called overheating. The consequences of overheating: one is to accelerate the wear between friction pairs, and the other is that the excessive heat continues to accumulate, which will burn the friction surface and cause a major accident of the machine. The main causes of bearing overheating are: uneven fit between bearing and journal or too small contact area; The bearing is skewed and the crankshaft is bent, the viscosity of the lubricating oil is too small, the oil circuit is blocked, and the oil pump is broken due to failure; During installation, there was no leveling, no clearance, no alignment between the main shaft and the motor shaft, and the two shafts were inclined.