What does SN mean in engine oil?
2 Answers
Engine oil SN represents the highest grade of engine oil, which is classified using a two-letter combination. The 'S' series denotes oils for gasoline engines, with specifications generally ranging from SA to SN. Each subsequent letter indicates improved performance over the previous grade, containing more additives to protect the engine. The further the letter is in the alphabet, the higher the quality grade. Most international brands offer engine oils at SF grade or above. Characteristics of engine oil: 1. Lubricity: The ability of engine oil to reduce friction, minimize wear, and prevent metal sintering under various conditions is called lubricity; 2. Low-temperature operability: The performance of engine oil to ensure easy starting and reliable oil supply in low-temperature conditions is called low-temperature operability; 3. Viscosity-temperature characteristics: The property of lubricating oil to change viscosity with temperature fluctuations is called viscosity-temperature characteristics.
I've been driving for over a decade, and the SN oil rating is really important. It's actually a performance grade standard set by the American Petroleum Institute (API), with SN being one of the more advanced levels. My previous car's manual specifically recommended using SN or SP grade oil, meaning this type of oil performs better in terms of cleaning and anti-wear properties, protecting the engine from carbon buildup and reducing friction noise. Last year, I switched to a full synthetic SN-grade oil and immediately noticed smoother idling and a slight reduction in fuel consumption. Many new cars now specify this grade because it's also designed to reduce emissions, making it more environmentally friendly. Just remember to maintain regular service intervals—using the wrong oil grade could lead to premature engine failure.
