You may have noticed that some engine oils claim to be synthetic oil, which sounds like a good idea to avoid the use of petroleum-based products. But what is really meant by synthetic oil? Is it any good for my car? And does it really help the environment?

The best synthetic oils offer more mileage, keep the engine cleaner, perform equally well in low and high temperatures, and protect your engine by keeping wear at bay. But some automotive enthusiasts will argue that conventional oil performs the same as synthetic oil, adding that synthetic oil is simply marketing. And it does help the environment - not because it’s made from green products, but because you need to change it less often than regular oil. But one thing is certain - you’re going to pay a higher price for synthetic oil.

The most important thing is to stick with the recommended viscosity. If your owner’s manual says 5W30, or 15W40, or 10W60 as an oil viscosity grade, that’s what you need to use.

So let’s dig in. There are several terms used to describe the varying degrees of synthesis in engine oil:

• Fully synthetic engine oil

• Synthetic technology engine oil

• Synthetic blend engine oil

• Conventional (mineral) engine oil

‘Fully synthetic’ engine oil consists of chemical compounds that are artificially made, with no petroleum products involved. Manufacturers of high performance European cars have been recommending fully synthetic motor oils for well over a decade.

Synthetic engine oils provide better engine protection than mineral oils, especially from wear and corrosion, and they also contribute to engine cleanliness, since they create practically no residue. Additionally they reduce internal resistance, thus increasing engine power and torque, and reducing fuel consumption. Lastly they provide a lower level of exhaust emission.

‘Synthetic technology’ oil is produced by mineral refining with chemical treatment, meaning that petroleum products are used in its manufacture but the additives are completely identical or similar to those in synthetic engine oils. This engine oil category is especially common among freight vehicles or motorcycles. Synthetic technology engine oils represent great value for money.

As its name implies, ‘synthetic blend’ engine oils are made out of a combination of mineral and synthetic base oils, with the right additives. Also called synthetic-based engine oils, they contain additives whose composition is identical or similar to mineral engine oils, which is why synthetic-based engine oils are, as far as their quality is concerned, closer to mineral engine oils. They are simply a cheap alternative to fully synthetic or synthetic technology oils - ideal for vehicles that are over 10 years old, or that have gone over 200,000 km.

Conventional (mineral) engine oils are refined from petroleum products, with no synthetic ingredient in sight. These oils are less resistant to high temperatures and oxidation compared to synthetic engine oils, which is why they have to be changed more often. But they have higher liquid points, which makes them favorable for winter conditions and extremely low temperatures.

In summary, if you have a brand new or a fine tuned car, it’s worth using a fully synthetic oil, for optimal performance and longer life. But if your vehicle has seen better days, or has a high mileage, it’s probably sensible to go for a blend or even a conventional motor oil. Whichever you choose, make sure you get the correct viscosity grade, as recommended for your vehicle model.

This month April 2021 we’re running a special 15% discount offer on our full range of Castrol and Shell lubricants - from 8th - 14th April. These include synthetic and mineral engine oils. Choose wisely. And happy motoring!

References:

https://www.castrol.com/en_us/united-states/home/motor-oil-and-fluids/engine-oils/motor-engine-oil-types/full-synthetic.html

https://www.total-serbia.rs/en/advice-proposals/ehow/differences-between-mineral-synthetic-and-synthetic-based-engine-oil

https://www.autoguide.com/top-12-best-synthetic-oils-you-can-buy