How to Identify Engine Oil Grades?
4 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.
I enjoy tinkering with car parts, and oil viscosity ratings are one of my research basics. SAE ratings like 10W-40 are key to viscosity grading: the lower the number before the W, the better the low-temperature performance; the higher the number after the W, the more robust it is in high-temperature environments. API standards such as SN or SP are also important, indicating the protection level; newer car models match higher ratings for improved efficiency. Base oils are divided into synthetic and mineral types—synthetic oil is more expensive but lasts longer. Climate plays a big role: in sub-zero regions, use lower W values to avoid starting difficulties; speed enthusiasts can opt for higher viscosity for enhanced protection. Don’t blindly trust brands when buying oil—checking the car manual is the most reliable. Mixing oils is fine short-term but can lead to sediment buildup over time. Fuel-efficient oils like 0W-20 can save 3-5% on fuel, but the engine must support it. I use a mobile app to track oil info for easy reference. Poor maintenance accelerates engine wear, leading to soaring costs—don’t underestimate it.
Having driven for decades, the oil grading system was much simpler back then. In my youth, a single number like SAE 30 would suffice, but now we have more detailed classifications like 5W-40. I’ve gotten used to checking the number after the W—using 30 or above in hot weather and lower W values in cold weather for easier starts. Clear labeling is key; just avoid the cheapest oils. The manual always recommends matching specifications—I once made the mistake of using the wrong oil, and the engine roared for a long time before starting. New oil cans with energy-saving certifications are more reassuring; they slightly reduce fuel consumption. Changing oil yourself isn’t hard—just wear gloves to stay clean. Regularly check oil levels to keep them normal. Don’t exceed 5,000 kilometers between oil changes, or sludge builds up. Saving money isn’t the priority—engine health comes first.
