How to Differentiate Engine Oil Grades?
2 Answers
Engine oil grades are classified based on quality and viscosity ratings. Oil for gasoline engines is typically denoted by the letter S, while oil for diesel engines is usually marked with the letter C. Engine oil consists of base oil and additives, where the base oil is the main component of the lubricant, determining its fundamental properties, and additives are used to compensate for the shortcomings of the base oil. The specifications for S-series oils include: SA, SB, SC, SD, SE, SF, SG, SH, SJ, SL. The specifications for C-series oils include: CA, CB, CC, CD, CE, CF, CF2, CF4, CG4, CH4, C14. As the letters progress, the grade of the oil increases. When both letters appear, it indicates that the oil is universal and can be used for both gasoline and diesel engines.
As a veteran driver with over a decade of experience, I primarily distinguish oil grades by those number-letter combinations on the bottles. The SAE viscosity rating like 5W-30 is key - the number before W (e.g., 5) indicates cold-weather fluidity (lower numbers mean easier cold starts), while the number after W (e.g., 30) shows high-temperature viscosity (higher numbers offer better engine protection). API service categories like SP represent the latest performance standards, reducing sludge and wear. I always check the vehicle manual when selecting oil to ensure manufacturer recommendations. Using wrong oil (e.g., high viscosity in low-viscosity engines) can spike fuel consumption and cause engine knocking. Synthetic oils, though pricier, offer superior durability - regular changes can extend engine life by 5+ years. Remember, certification marks like the API donut are quality guarantees - don't cut corners only to pay dearly later.
