Operating conditions such as the engine’s temperature, position, size, pressure and shaft speed largely determine which individual oil seal composition is most suitable for every individual application.

Cassette seals are designed to maximise grease or oil retention and protection against liquid or solid contaminants. These seals are provided with their own bushings in which dirt is kept out and oil/grease kept in by a multi-lip seal.
Conclusion
Heat and attrition are generated by the parts moving against each other. The sealing function can only be ensured if an intentional defined leakage of oil is able to exit for seal lubrication, preventing seal wear and possible failure, while a tight static seal between shaft and sealing lip must be assured when the shaft is stationary.
Oil seals for cars
Proper techniques and diligence during oil seal installation will result in what seems like an unremarkable situation – a component holding its lubrication. When something you’ve installed works effectively and quietly, you know you’ve done it right.
The material of the sealing lip is chosen according to the liquid to be sealed and the rotational speed. For larger shafts, an NBR sealing lip can cope with surface speeds of up to 10-12 m/s, while an FKM lip is suitable for speeds of up to 35-38 m/s.