Semi Synthetic and Fully Synthetic Oil

Using the right oil will keep your car running smoothly and its engine delivering its full potential and performance.

Engine oil works hard. It reduces friction, helps manage engine temperature and protects the hardworking components. Your engine oil should be changed at least every year as part of an annual service, but what’s the difference between semi and fully synthetic oil and what’s best for your car?

What’s the difference between semi-synthetic oil or fully synthetic oil?

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.

Oil manufacturers ensure that synthetic oils have none of the impurities found in mineral oils. They’re thinner, which means fuel efficiency is improved and they last long too.

There are two types of synthetic oil: semi-synthetic oil and fully synthetic oil.

Semi synthetic oil

Semi synthetic oils are a mixture of synthetic and mineral oil. They’re cheaper than fully synthetic oil, but don’t reach the same levels of performance and engine protection.

Fully synthetic oil

Fully synthetic oils are 100% synthetic and aren’t mixed with mineral oil.

They deliver the highest levels of performance and are an essential requirement for many modern engines. In fact, using a poor grade engine oil could damage your engine, so always use the best.

Don’t know what grade oil you need?

You’ll find details of the manufacturer’s recommended grade and brand of engine oil in your car’s handbook. If you can’t find the details, contact Halfords or drop into a local store and we’ll be happy to help you.

What oil do you use at Halfords?

We insist on using the best, which is why we use high-quality fully synthetic oil at all Halfords Autocentres.