What are the classifications of engine oil grades?
2 Answers
Engine oil, also known as engine lubricant. The classification of engine oil grades is based on quality grades and viscosity grades. Below are the specific details about engine oil grades: 1. Quality grade classification: The "S" series represents oil for gasoline engines, while the "C" series represents oil for diesel engines. From "SA" up to "SN", each subsequent letter indicates better performance than the previous one. The further the letter is in the alphabet, the higher the quality grade, making the engine oil more effective. 2. Viscosity grade classification: The "W" stands for Winter. The smaller the number before the "W", the better the low-temperature fluidity of the engine oil.
When it comes to oil grades, I think there are two main categories: viscosity and service ratings. Viscosity is indicated by the SAE standard, such as 5W-30 or 10W-40. The smaller the number before the W, the smoother the engine starts in winter—something I pay special attention to when driving in northern regions. The larger the number after the W, the better it protects the engine from thinning in high summer temperatures. Service ratings like API’s SN or SP—the newer the letter, the better. Currently, SP is mainstream, helping reduce carbon buildup and fuel consumption. Remember, all this info is on the oil label—don’t choose oil based on gut feeling; check the manual’s recommendation. My car’s manual specifies 5W-30 API SN, and sticking to it keeps the engine running longer. Using high-viscosity or outdated grades may cause wear or contamination—saving a few bucks on oil changes isn’t worth damaging the engine. Standards like ILSAC’s GF are generally compatible with API, so a quick glance when buying oil gives peace of mind. In short, understanding these grades makes maintenance easier—don’t overlook the small details.
