Synthetic oils are specifically manufactured to provide consistent, superior performance. Their main advantage over mineral oils is that they protect the engine across a far wider range of temperatures – up to an engine’s maximum temperature and beyond, and they are thinner, helping to improve fuel efficiency. They offer the highest levels of performance and are an essential requirement for many modern engines.
Semi synthetic oils are a mixture of synthetic and mineral oil. Engines requiring semi synthetic oil must use at least semi synthetic oil (not mineral oil) but may benefit from upgrading to fully synthetic oil for increased protection and performance.