How it works – Synthetic vs. Mineral oil

Both synthetic and conventional engine oils are extracted from the ground…and here the similarities end.

Using the correct engine oil keeps your engine running smoothly. Engine oil stops the metal surfaces in your engine from grinding together and wearing, by creating a separating oil film between them. The oil also disperses heat. Beside that, oil prevent dirt build-up and deposits by keeping them in suspension and protects against sludge and fights oxidation, keeping the oil fresh and minimising acids which can cause corrosion.

There are two main types of oil on the market: mineral (conventional) and fully synthetic. Motor oils labelled as part- or semi-synthetic or synthetic  contain mixture of these two types.

Mineral oil is processed in a refinery to separate out the fractions with useful lubrication properties and remove unwanted components such as waxes while the synthetic oil is made from more advanced refining processes and are of a higher purity and quality than conventional mineral oils or semi-synthetic oils. This not only removes more impurities from the crude oil but it enables individual molecules in the oil to be tailored to the demands of modern engines, so with that you get higher levels of protection and performance. Synthetic oils have higher performances because are manufactured using more expensive chemical process than that used in mineral oil production, and from that a higher price per liter. Synthetics may have better viscosity film strength than petroleum stocks at elevated temperatures.

The typical composition of motor oil have 75-90% of base oil and 10-25% additives. But don’t assume that if a synthetic is good/expensive, then you don’t need to change it as often. The base may be good, but the additive package, which can be as much as 25%, can still become exhausted. And unburned fuel, partially burned hydrocarbons, atmospheric dirt, metal wear particles will build up fast in a synthetic lubricated engine as in one laved in mineral oil. The only way to remove this stuff is to drain and replace the oil.

Conventional oil is formatted with additive packages to ensure that it has proper heat tolerance, breakdown resistance, and viscosity that engines require. So far many vehicles, conventional oil is sufficient to get the job done.

Another advantage of the synthetic oils vs mineral debate is that they’re cleaner and more environmentally friendly, helping to cut engine emissions when compared to mineral oils. Mineral oils also contain greater amounts of impurities, such as sulfur, reactive and unstable hydrocarbons and other undesirable contaminants that cannot be completely removed by conventional refining of crude oil.

So, which one should be chose? Synthetic or mineral? Well, depends. Depends on what you want from your engine. Some high-performance cars come from factory with synthetic oil, so in this case you should remain on synthetic, or if the motor is overloaded, or the car is pulling often heavy weights.


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