Synthetic oils are man-made oils that can be used in your car. On the shelves you’ll see both semi synthetic oil and fully synthetic oil for sale. Here, we explain the difference between each type of oil and how you can choose what’s best for you and your car.
Using the right oil will keep your car running smoothly and its engine delivering its full potential and performance.
Engine oil works hard by reducing friction, helping manage engine temperature and protects the hardworking components. Without engine oil, your car would seize up in seconds, so it’s vital to ensure it’s topped up and that you’re always using the right type of oil.
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. They’ll safely regulate your car engine's maximum temperature, reducing the risk of overheating.
Oil manufacturers create synthetic oils with none of the impurities found in mineral oils. They’re thinner, too, which means fuel efficiency is improved and they last longer which can save you cash.
There’s not one type of synthetic oil, but two: semi-synthetic oil and fully synthetic oil.
Semi synthetic oil
Semi synthetic oils are a mixture of synthetic oil 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% man-made 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 we recommend you always use the best.
What oil do I need for my car?
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 only use high-quality fully synthetic oil at all Halfords Autocentres. When booking a car service or oil replacement, always check what’s being used on your car.
Which is better semi-synthetic or fully synthetic oil?
Fully synthetic oils will deliver better performance than semi-synthetic oils. They cost slightly more, but they will last longer than semi-synthetic oils. They will also operate better at higher temperatures, keeping your engine running smoothly whatever your driving style or road conditions.
What happens if I use semi-synthetic oil instead of fully synthetic?
It’s vital that you use the right oil for your car, or you could damage your engine. Check your manufacturer’s handbook to find the right oil for your car engine. Semi-synthetic oil shouldn’t damage your car’s engine, but as previously mentioned, it may not deliver the best performance.
Is fully synthetic oil better?
Yes, fully synthetic oil if better than semi-synthetic oil. It’s manufactured to higher standards and delivers better performance across all parameters. We reckon it’s worth the extra cost as an investment in the long-term of your car.
Can I mix fully synthetic and semi-synthetic oil?
Yes, you can mix synthetic oils and semi-synthetic oils, but you probably shouldn’t. Mixing them could change the characteristics of the oil and reduce its performance, so it’s not recommended.