What is the color differentiation of Toyota valve stem seals?

[OKaden]

Toyota valve stem seals are color-coded with black for exhaust valves and gray for intake valves. Below is relevant information about valve stem seals:1. Introduction: A valve stem seal is a type of oil seal, typically composed of an outer skeleton and fluororubber vulcanized together. The seal's inner diameter is equipped with a self-tightening spring or steel wire, used for sealing the engine valve guide.2. Function: Valve stem seals prevent engine oil from entering the intake and exhaust pipes, avoiding oil loss. They also prevent leakage of the air-fuel mixture and exhaust gases, and stop engine oil from entering the combustion chamber. As one of the critical components in the engine valve train, valve stem seals operate in high-temperature environments exposed to gasoline and engine oil, thus requiring materials with excellent heat and oil resistance, usually made from fluororubber.