What is the Engine Oil Grade Chart?
3 Answers
The following are the quality grade evaluation standards established by the American Petroleum Institute (API) for engine oils: 1. Gasoline engine oil: "S" stands for gasoline engine oil. "L" indicates the grade, ranging from API SA, SB, SC, SE, SF, SG, SH, SJ, SL, SM. The further the letter in the alphabet, the higher the oil grade. SL is currently the highest quality grade of engine oil in the world. 2. Diesel engine oil: "C" stands for diesel engine oil. "F" indicates the grade, ranging from API CA, CB, CC, CD, CE, CF, CF-4, CG-4, CH-4. The further the letter in the alphabet, the higher the oil grade.
I think the oil viscosity chart is just a simple guide showing you how to choose the right oil to protect your engine. Like what veteran drivers taught me when I was learning to drive, the chart lists various number combinations, such as 5W-30 or 10W-40. The 'W' stands for winter, and the smaller the number before it, the smoother the cold starts in winter. The larger number after indicates higher viscosity at high temperatures, which helps prevent engine wear. This chart is usually printed on oil containers or found in maintenance manuals, making it easy to see which oil suits your car. Choosing the wrong oil is a no-go—it can damage the engine and waste fuel, so I always check the chart before an oil change to ensure it matches the climate and my car model. With weather changes being more extreme these days, in the north, you need oil with a lower 'W' number, while in the south, a higher one might be safer. Overall, this chart makes maintenance a no-brainer—pretty practical and convenient.
The oil grade chart is essentially a viscosity coding system for me, based on the grades defined by SAE standards. From my own experience, every time I refer to the chart in the garage, it categorizes oils into various codes. For example, in 5W-30, the number 5 before the W indicates low viscosity at cold temperatures, ensuring quick lubrication during startup, while the 30 after W represents the high-temperature viscosity value—the higher the number, the better the protection. The chart also integrates API quality grades, such as SN or SP, indicating cleanliness and durability. When choosing oil, I always consult the chart first, selecting the correct grade as per the car manual to avoid mixing errors. Remember, different seasons or driving conditions affect the choice—urban driving often calls for lower viscosity like 0W-20 for fuel efficiency, while off-roading requires thicker oil to withstand impacts. In short, this chart is the foundation for scientifically selecting oil, indispensable for both novices and veterans.
