1. For the spin-on filter (iron shell), the rotation force is too large, exceeding the standard 20-60 Newtons (1 kg = 9.8). The correct installation is to use 2 kg of hand rotation force. Do not use a wrench to install or rotate the filter. When the force is greater than 2.5 kg, it is easy to cause the sealing ring to deform and produce protruding points along the circumference. Under the impact of high-pressure air flow, gaps will occur and leakage will occur.

2. The flat dirt in contact with the old oil filter has not been cleaned.

3. When disassembling the old oil filter, due to the excessive rotational force in the previous time, the old sealing ring stuck to the filter seat, and the new oil filter leaked oil after being installed.

4. The lubrication system is seriously polluted, and heavy oil scale blocks the main oil passage (or the sealant blocks the oil passage after overhaul), causing internal pressure and impacting the sealing ring, causing oil leakage.

5. For environmentally friendly filter elements (paper filter elements), most of them are caused by the fact that the inner sealing ring of the guide rod is not removed and a new sealing ring is installed.

6. When replacing the environmentally friendly filter element (paper filter element), a new inner sealing ring was not replaced.

7. The environmentally friendly filter element (paper filter element) still has too much rotational force on the outer sealing ring (large one), causing serious deformation or hidden damage, and being impacted under pressure during work and causing oil leakage.