How to Differentiate Engine Oil Grades?
3 Answers
Engine oil grades can be differentiated as follows: 1. From "SA" up to "SL", each subsequent letter indicates improved performance over the previous grade, with more additives to protect the engine. 2. The later the letter in the alphabet, the higher the quality grade. Most international brands offer engine oils above SJ grade. SA is pure mineral oil without additives; SB contains some rust and oxidation inhibitors; SC provides protection against high/low temperature deposits, wear, rust, and corrosion; SD performs better than SC; SE offers enhanced protection against oxidation, rust, corrosion, and high-temperature deposits; SF has better oxidation stability than SE; SG provides superior control over engine deposits, oil oxidation, and engine wear compared to SF; SH has more stringent testing procedures than SG; SJ represents world-class engine oil; SL is an upgraded version of SJ grade.
When I first started driving, I was quite confused about engine oil. Later, I learned that there are mainly two sets of standards: API and SAE. API standards like SN and SP represent performance levels, with SP being the latest and higher standard offering better cleaning and engine protection. SAE is the viscosity rating, such as 5W-30: the 'W' in 5W stands for winter, indicating good fluidity at low temperatures for easier starts, and 30 represents the viscosity at high temperatures to ensure lubrication and prevent wear. Choosing engine oil depends on your car manual's recommendation to match your engine model—don’t switch randomly, or it may accelerate wear and increase fuel consumption. In northern winters, I use 5W low-viscosity oil, which makes starting smoother and saves a bit of fuel, saving money and hassle in the long run. Remember this tip: the oil bottle label clearly states the rating—beginners can just check the manual without overcomplicating things. Keep it simple to avoid confusion when starting out.
As someone who frequently works on car repairs, understanding oil grade distinctions is crucial. The SAE viscosity rating, such as 0W-20, has key components: the 0W number indicates low-temperature fluidity, meaning better cold starts and quick oil pumping even in sub-zero conditions; the 20 represents high-temperature viscosity, preventing excessive friction and protecting components. API performance ratings like SP outperform older SN grades with superior oxidation resistance, reducing carbon buildup and extending engine life. In practice, I recommend adjusting based on vehicle type: older cars may use 10W-40, while turbocharged vehicles must select SP-grade oil matching specifications to prevent increased noise or oil consumption. When inspecting used oil, if it appears black or has sediment, consider upgrading the API grade. Don't overlook seasonal impacts – prioritize lower W-value oils like 0W or 5W in cold regions to ensure startup efficiency. Always follow the manual's recommendations as the baseline rather than relying solely on experience to avoid repair issues, saving money while maintaining safety.
