What is the difference between SN, SP, and SL engine oils?
1 Answers
API grades represent the quality levels of engine oil, using simple codes to describe the working capability of the oil. Engine oil grades range from SA to SP, with letters further in the alphabet indicating higher quality. Currently, the more common grades are SL, SM, and SN. Below are the differences between SN, SP, and SL engine oils: 1. Thickness varies: The difference between SN and SP lies in the thickness of the oil at certain temperatures, i.e., the difference in viscosity (phosphorus content). SN oil has relatively lower phosphorus content. Moreover, when comparing the viscosity of SN and SP oils, SP has a higher viscosity value, indicating that SP forms a stronger oil film than SN, providing better protective performance. Additionally, SP offers stable improvements over SN in terms of noise reduction, fuel consumption, and acceleration performance. 2. Different grades: SP is currently the highest grade for gasoline engine oils. The higher the oil grade, the better its technical indicators, which can significantly extend the engine's lifespan, prolong oil change intervals and maintenance cycles, and reduce vehicle maintenance costs. 3. Differences in oxidation resistance and wear resistance under high-temperature and high-speed operation conditions: SN has superior high-temperature detergency compared to SL. SN-grade oil offers better oxidation stability and anti-wear properties. Since SN oil contains lower levels of phosphorus and zinc than SL oil, it reduces wear on the three-way catalytic converter.
