What do S and C stand for in engine oil?
2 Answers
S stands for gasoline engine-specific oil, while C stands for diesel engine oil. Introduction to Gasoline: Engine oil is crucial for the engine. It not only lubricates but also cleans, seals, cushions, prevents rust, and dissipates heat. When the engine is running, the oil forms a thin film on the surfaces of various engine components, preventing direct contact and friction between them. Introduction to Diesel: Diesel is a light petroleum product and a complex mixture of hydrocarbons, serving as the fuel for diesel engines. It is primarily produced by blending diesel fractions obtained from processes such as crude oil distillation, catalytic cracking, thermal cracking, hydrocracking, and petroleum coking. It can also be derived from shale oil processing and coal liquefaction.
When I first started learning to drive, I was also confused about the meaning of 'S' and 'C' on engine oil bottles. Later, I learned that 'S' stands for lubricants specifically designed for gasoline engines, known as 'Service' categories in English, such as the common SN or SP grades; while 'C' refers to lubricants for diesel engines, meaning 'Commercial' categories. Using the wrong oil can cause serious issues. For example, using diesel engine oil in a gasoline car may lead to insufficient cleanliness and increased engine carbon deposits; conversely, using gasoline engine oil in a diesel car may result in poor anti-wear properties and accelerated component wear. The maintenance manual will specify the oil requirements. It's best to follow the guidelines and use API-certified products during regular oil changes, which can effortlessly extend the engine's lifespan by tens of thousands of kilometers.
