How are oil grades classified?
2 Answers
Oil grades are classified as follows: 1. AB series: for gasoline and light-duty diesel engine oils; 2. C series: for catalyst-compatible engine oils; 3. E series: for heavy-duty diesel engine oils. The functions of engine oil are: 1. Cooling and temperature reduction; 2. Sealing and leak prevention; 3. Cleaning and purification; 4. Shock absorption and buffering; 5. Lubrication to reduce wear; 6. Rust and corrosion prevention; 7. Component protection. Engine oil, also known as engine lubricating oil, is composed of base oil and additives. Base oil is the main component of lubricating oil, determining its fundamental properties, while additives compensate for and improve the shortcomings of the base oil's performance.
When it comes to oil grades, I think they're mainly classified by viscosity, which affects a car's performance in both cold and hot weather. Take those numbers like 0W-20 on the label - the number before the W represents winter low-temperature fluidity. The smaller the number, the better it flows in freezing conditions, protecting the engine from cold damage. The number after W indicates high-temperature viscosity - the higher the number, the thicker the oil, which suits older cars used for long drives or heavy hauling. When choosing oil for my own car, I always check the manual's recommendations and avoid randomly using high-viscosity oils, as they waste fuel and increase wear. For some vehicles like SUVs doing long mountain drives in summer, I'd pick 40 viscosity; for small city cars in winter, 20's low viscosity runs smoother, being both convenient and eco-friendly. In short, getting the right match extends engine life and saves money and hassle.
