How to Identify Engine Oil Grades?
2 Answers
Methods to identify engine oil grades: The 'S' series represents oil for gasoline engines, while 'C' denotes oil for diesel engines. When both 'S' and 'C' appear simultaneously, it indicates a universal oil suitable for both gasoline and diesel engines. The oil quality ranges from SA up to SL, with later letters in the alphabet indicating higher quality grades. Each subsequent letter signifies improved performance over the previous one, as the oil contains more additives to protect the engine. The oil grades for winter and summer also differ. Winter oil grades are: 0W, 5W, 10W, 15W, 20W, and 25W. The symbol 'W' stands for 'Winter,' and a smaller number before 'W' indicates lower low-temperature viscosity, better low-temperature fluidity, and suitability for lower minimum temperatures. Summer oil grades are: 20, 30, 40, and 50, where a larger number indicates higher viscosity and suitability for higher maximum temperatures.
When I first started learning about car maintenance, I was completely baffled by oil grades like SAE 5W-30. Now I understand that the number before the W, such as 5, indicates low-temperature fluidity—the lower the number, the smoother the cold starts. The number after the W, like 30, represents high-temperature protection—the higher the number, the better the engine protection in hot weather. Living in the north, I choose 0W or 5W for winter and a higher grade like 40 for summer; friends in the south can start with 10W. Remember to check the manual for detailed recommendations—don’t just rely on advertisements. Using the wrong oil can lead to increased fuel consumption or engine noises, with repairs costing thousands. Brand differences are minimal; the key is matching the oil to the climate and vehicle condition. Regularly check the dipstick—new oil should be clear and transparent. Older cars may need higher viscosity oil to reduce wear. Develop a habit of recording oil change dates to avoid delays.
