Should Older Cars Use Full Synthetic or Semi-Synthetic Engine Oil?

[DeStella]

It is better to use full synthetic engine oil for the maintenance of older cars. Full synthetic engine oil has the following advantages compared to semi-synthetic engine oil: 1. Better high and low-temperature performance: Full synthetic oil has a wider operating temperature range and a longer service life. For the same oil film requirements, synthetic oil can achieve the desired protection with lower viscosity, whereas semi-synthetic oil requires a relatively higher viscosity to meet the same requirements. This means that under the same working conditions, full synthetic oil can protect the engine with lower viscosity. 2. Longer oil change intervals: Engine oil blended with synthetic oil has stronger oxidation resistance, significantly extending the oil change interval. Although the initial investment in oil may be higher, it reduces the frequency of oil and filter changes. Generally, engines using full synthetic oil can extend the oil change interval to 7,500-10,000 kilometers.