What level is SN on engine oil?
2 Answers
SN on engine oil belongs to the second-grade gasoline engine oil level. Currently, the main gasoline engine oils still in use are SJ, SL, SM, and SN, with the highest grade being SP. Engine oils starting with "S" are specifically for gasoline engines and cannot be used in diesel vehicles. When choosing engine oil, you should not only consider what types of vehicles SN-grade oil is suitable for but also its viscosity. Even within the same SN grade, there can be different viscosity indices. The viscosity determines the oil's high and low-temperature performance, with the low-temperature flow characteristics and high-temperature viscosity determining the applicable range of the oil.
When changing my engine oil, I noticed the SN designation and got curious, so I looked it up. SN is one of the quality classifications for gasoline engine oils established by the American Petroleum Institute (API), and it's relatively new in modern standards, widely adopted post-2020. Compared to the older SM grade, SN places greater emphasis on protecting turbochargers, reducing carbon deposits, and extending the lifespan of catalytic converters, making it highly suitable for most modern cars we drive today by preventing pre-ignition issues. After switching to SN-grade oil in my own car, I noticed smoother engine operation and reduced noise, likely due to its compatibility with high-compression engines. When purchasing oil, don’t just focus on viscosity—choosing the right grade is crucial to avoid potential engine damage and unnecessary expenses. I recommend checking your vehicle’s manual to ensure compatibility. In short, SN is a cost-effective choice, especially recommended for hybrid or SUV owners.
