The cavitation of the wet cylinder liner has become a prominent problem, so some diesel engine cylinder liners have three sealing rings.

The upper upper half is in contact with the coolant, which can prevent the mating surface from rusting, easy to disassemble, and can borrow Absorb vibration to reduce cavitation.

Some of the upper and middle sides use ethylene-propylene synthetic rubber to seal the coolant; the next one is made of silicone material to seal the oil, and the two cannot be misplaced. Some also put the seal on the cylinder.