What are the classifications of engine oil?
3 Answers
Engine oil is classified into: mineral oil, synthetic oil, and vegetable-based oil. The viscosity grade of engine oil is generally classified according to the international SAE standard, which includes single-grade oil and multi-grade oil. For example, SAE30 and SAE40 are single-grade oils, while SAE10W30 and SAE15W40 are multi-grade oils. Engine oil, also known as engine lubricant, serves to lubricate and reduce friction, assist in cooling, seal against leaks, prevent rust and corrosion, and provide shock absorption. It is often referred to as the "blood" of a car. Engine oil consists of two main components: base oil and additives. The base oil is the primary component of the lubricant, determining its fundamental properties, while additives compensate for and improve the shortcomings of the base oil, providing certain new characteristics. Additives are an essential part of the lubricant.
Engine oil classification mainly depends on two factors: viscosity and grade. Look at the SAE 5W-30 or 0W-40 on the bottle. The smaller the number before the W, the better the low-temperature fluidity, while the number after represents high-temperature viscosity. In northern winters, 5W or 0W ensures quicker starts, while southern regions or older cars may need thicker oils like 40. As for grades, from API's SN to the latest SP, the later the letter, the better the performance. Nowadays, mainstream new cars require at least SN-grade oil. Fully synthetic oil offers significantly better protection than mineral oil, making it ideal for turbocharged cars or frequent highway driving. Personally, I always pay close attention to these parameters during maintenance.
From my practical maintenance experience, engine oils can be effectively categorized into three types: Mineral oil is inexpensive but requires shorter change intervals, semi-synthetic offers the best value for money and suits regular family cars, while full synthetic is the most expensive but can extend oil change mileage up to 10,000 km. The most crucial factor is viscosity matching - Japanese cars commonly use thin 0W-20 oil like milk, whereas German vehicles typically require thicker 5W-40. For China VI emission standard vehicles, special attention must be paid to GPF certification to avoid clogging the particulate filter. When selecting oil, always check the certification standards required in your manual - this is far more important than simply looking at brand names.
