Is SN Engine Oil Fully Synthetic or Semi-Synthetic?
2 Answers
SN engine oils are all fully synthetic, and SN is the highest grade. Engine oils starting with 'S' are specifically for gasoline engines, meaning they cannot be used in diesel vehicles. The grades of engine oil are categorized into twelve levels: SA, SB, SC, SD, SE, SF, SG, SH, SJ, SL, SM, and SN. With each increasing letter, the performance of the engine oil improves over the previous one. Although SN-grade engine oil offers the best performance, it is advisable to use the grade specified by the engine manufacturer. Effects of Low Viscosity Engine Oil on Vehicles: Increased oil consumption, often leading to what is commonly referred to as 'oil burning.' It also results in incomplete combustion, increased carbon deposits in the combustion chamber, and reduced engine power. Poor sealing performance can cause cylinder leakage, decreased power, and contamination of the oil. Insufficient oil film strength makes it prone to breakdown, accelerating wear between components, and over time, noise levels increase. Effects of High Viscosity Engine Oil on Vehicles: Difficulty in cold engine starts and increased dry friction, which exacerbates component wear. Increased frictional resistance between components reduces engine power. Reduced flowability diminishes the cleaning effectiveness for impurities.
SN engine oil actually refers to the API SN performance standard, not a synthetic type. API SN is an oil specification by the American Petroleum Institute, primarily focusing on high-temperature protection and cleaning capabilities for modern engines, without specifying whether the oil is synthetic or semi-synthetic. In the market, you can find SN oils labeled as full synthetic, semi-synthetic, or even mineral oil, with differences lying in the base oil and additives. Full synthetic oils are purer, have better oxidation resistance, longer oil change intervals, and smoother cold starts; semi-synthetic oils are a middle ground, more affordable but with slightly less protection. When choosing, don’t just look for SN—check the packaging to see if it’s clearly labeled as synthetic or semi-synthetic, and decide based on your car’s engine and driving habits. I always recommend older car owners use full synthetic SN oil because it reduces carbon buildup and extends engine life, especially for long-distance or high-frequency driving, providing greater peace of mind.
