Valve stem seal is a kind of oil seal, which is generally made of vulcanization of the outer skeleton and fluoroelastomer, and the oil seal diameter mouth is installed with a self-tightening spring or steel wire for the sealing of the engine valve guide rod. The valve oil seal can prevent the oil from entering the intake and exhaust pipes, avoid the loss of oil, prevent the gasoline and air mixture and exhaust gas leakage, and prevent the engine oil from entering the combustion chamber.
