What are the components of engine oil?
4 Answers
It is composed of base oil and additives. Composition of engine oil: Engine oil consists of base oil and additives. Base oil is the main component of lubricating oil, determining its fundamental properties. Additives can compensate for and improve the performance of the base oil, imparting it with new characteristics, making them an essential part of lubricating oil. Classification of engine oil: The SAE viscosity classification for winter engine oil grades includes: 0W, 5W, 10W, 15W, 20W, 25W. The symbol W stands for winter. The smaller the number before W, the lower the low-temperature viscosity, the better the low-temperature fluidity, and the lower the applicable minimum temperature.
Engine oil is essentially a blend of base oil and a bunch of additives. The base oil is the main component, accounting for 70-80%, and is divided into three types: mineral oil, semi-synthetic oil, and full-synthetic oil. Mineral oil is directly refined from petroleum and has the lowest cost; full-synthetic oil is chemically synthesized in a lab and offers the most stable performance. The additives are the key technology—detergents and dispersants are specifically designed to clean engine carbon deposits, anti-wear agents form a protective film on metal surfaces to reduce friction, and antioxidants extend the oil's lifespan. Each additive exists to solve a specific problem; for example, antifreeze and anti-gel agents must be added to oil used in northern winters. So when choosing engine oil, don’t just look at the grade—check whether its additive formula is suitable for your car.
I've just researched motor oil composition. Simply put, it's like a formula drink: base oil is the liquid foundation, while additives are various flavorings. Mineral base oil is cheaper but prone to deterioration at high temperatures, whereas full synthetic base oil has neatly arranged molecules with good low-temperature fluidity and high-temperature oxidation resistance. Anti-foaming agents prevent oil from turning into milk foam, and viscosity index improvers keep the oil from solidifying in winter or thinning in summer. Some premium oils add molybdenum to reduce wear or boron-containing detergents to break down carbon deposits. Each oil change essentially replenishes these consumable additives, which is why regular maintenance is particularly important.
The formulation of engine oil is actually quite intricate. Mineral oil is derived from distilled crude oil, while full synthetic oil is chemically synthesized from raw materials like ethylene, featuring more uniform molecular structures. What truly protects the engine is the approximately 20% additive package: detergents prevent sludge from clogging oil passages, dispersants keep carbon particles suspended in the oil to avoid sedimentation, and anti-wear agents form a protective buffer layer on piston rings. Don’t underestimate the sealing components—they prevent oil leaks in older vehicles. I’ve seen people mix different brands of engine oil, but this practice can trigger chemical reactions between additives, ultimately harming the engine.
