Oil sealing is not strict is the main factor that causes oil leakage. When the axis is worn to form a groove, even if the new oil seal cannot be sealed, it is due to the decline in the contact pressure of the oil seal lip mouth and the shaft, resulting in too small the volume of the diameter and axis diameter after installation. Taking the S195 diesel engine crankshaft oil seal as an example, the main reason for analyzing the strict sealing is:

① The quality of oil seal manufacturing is poor;

② Poor quality of shafts or bearing;

③ Improper use of maintenance;

④ Improper installation;

⑤ Improper custody and adversely affected environmental pollution.