Finished oil seal are installed in metal housing and directly rubber – PTFE vulcanization with metal housing two kinds of methods. The traditional oil seals are always installed directly in engine cast iron housing body, due to inconvenience installation and removing, very easy to damage the housing shape deformation, happen oil leakage possible. This kind of oil seal using avoid this issue happen, according to the design of location holes of the installation metal housing, directly install the oil seal on the engine body with screw, very convenient to install and remove. The international OEMs are using this new type of structure oil seals.