What is the difference between synthetic oil and mineral oil?

[SanEllie]

Mineral oil and synthetic oil (synthetic oil can be further divided into semi-synthetic and full-synthetic) have the following differences: 1. Refining and composition: Mineral oil is directly refined from crude oil as the base, with additives mixed in. Semi-synthetic oil is based on mineral oil with synthetic oil additives, and its performance is very close to full-synthetic oil. Full-synthetic oil is 100% made from polyalphaolefin (PAO) or artificially synthesized esters. 2. Performance: Since mineral oil is directly refined from crude oil, it inevitably contains impurities. Full-synthetic oil is artificially synthesized, so it has the highest purity. Mineral oil < semi-synthetic oil < full-synthetic oil. 3. Price: Mineral oil < semi-synthetic oil < full-synthetic oil.

[CoreyDella]

The biggest differences between synthetic oil and mineral oil lie in their sources and performance. I often encounter these issues while driving. Mineral oil is directly refined from crude oil, contains impurities, and is cheaper, but it tends to solidify at low temperatures, making engine startup difficult. In summer, it evaporates quickly under high heat, requiring shorter oil change intervals—typically every 5,000 kilometers. Synthetic oil, on the other hand, is chemically synthesized with purer molecules. It doesn’t freeze even in sub-zero winters, maintains good fluidity, and remains stable without evaporating under high temperatures, offering better engine protection. The oil change interval extends to 8,000–10,000 kilometers, saving time and costs in the long run. From my experience, using synthetic oil reduces engine noise, ensures smoother acceleration, and even saves a bit on fuel. For long-distance driving or harsh weather conditions, it provides higher safety margins. I recommend new car owners prioritize synthetic oil.

[DePaisley]

The key differences between these two oils lie in their chemical structure and stability. Mineral oil is derived from crude petroleum with irregular molecules prone to oxidation, affecting longevity; synthetic oil is artificially formulated with uniform molecules that withstand high temperatures and pressures, ensuring smoother engine operation. After switching to synthetic oil, I observed its distinct advantages under extreme conditions: quicker cold starts, resistance to thermal breakdown, and reduced friction for more efficient acceleration. The extended oil change interval (nearly doubled) reduces maintenance frequency while being eco-friendly. Though mineral oil is cheaper, its rapid oxidation makes it suitable only for short-distance use. For high-performance vehicles or frequent drivers, upgrading to synthetic oil justifies the additional cost.

[DelHaven]

From a cost-saving perspective, mineral oil is cheaper, while synthetic oil has a higher initial cost. But I've calculated: mineral oil needs to be changed every 5,000 kilometers, whereas synthetic oil lasts 10,000 kilometers, saving half the maintenance cost. Mineral oil performs poorly in cold climates, potentially leading to higher engine repair costs; synthetic oil is more durable, reducing unexpected expenses. In the long run, it's worth the price.

[LaAutumn]

Having driven for many years, I've experienced the differences between the two. Mineral oil is naturally refined with more impurities, making it difficult to start in freezing temperatures; synthetic oil is artificially synthesized with high purity, protecting the engine like flowing water in winter. At high speeds in hot weather, synthetic oil remains stable without coking, with longer oil change intervals, saving time and effort. Mineral oil requires a trip to the shop every six months, which is annoying.