What is the difference between full synthetic oil and semi-synthetic oil?
2 Answers
Semi-synthetic oil and full synthetic oil are two classifications of engine oil. The difference between them lies in: full synthetic oil can be used in a wider temperature range and has a longer service life; for the same oil film requirements, synthetic oil can achieve this with a lower viscosity, while semi-synthetic oil requires a relatively higher viscosity to meet the same requirements. Below are the differences between semi-synthetic oil and full synthetic oil: 1. In the same working environment, full synthetic oil can protect the engine with a lower viscosity. In the same working environment, full synthetic oil has a much longer service life than semi-synthetic oil, thus it is more expensive. 2. Compared to semi-synthetic oil, full synthetic oil has the following characteristics: better high and low-temperature performance; longer oil change intervals; and is suitable for more severe vehicle conditions.
Fully synthetic oil is entirely manufactured through chemical processes, being a pure synthetic oil without any mineral oil components, providing top-tier protection; semi-synthetic oil, on the other hand, is a blend of mineral and synthetic oils, typically composed of about 30% synthetic oil and 70% mineral oil. This compositional difference gives fully synthetic oil superior performance: it ensures quick starts in extremely cold weather without freezing, and maintains stable oil film at high temperatures, reducing engine wear. In contrast, semi-synthetic oil offers weaker fluidity and protection but comes at a much lower cost. Having tried fully synthetic oil in my car, I noticed the engine runs quieter, and the oil change interval can extend up to a year or 10,000 kilometers; with semi-synthetic oil, changes are needed around 7,000 to 8,000 kilometers. If your car is a high-performance turbocharged model or frequently operates in harsh climates, I'd strongly recommend sticking with fully synthetic oil; for regular family cars, semi-synthetic is a cost-effective choice. Don’t just save money at the expense of neglecting maintenance intervals.
