WHAT DOES AN ENGINE OIL MADE OF?
All motor vehicles require lubrication to ensure the engine’s excellent performance. But what are engine oils made of? Whether it is synthetic, mineral, or semi synthetic, an engine oil is always made of base oil – crude petroleum or polymers – and additives with their unique compositions. To know more, let’s explore the three types.
Mineral engine oils
Mineral engine oils are derived from crude petroleum. After being extracted and conveyed to a refinery, crude oil undergoes several refining processes to remove as much impurities as possible. Mineral oils contain hydrocarbon, oxygenated or non-oxygenated, and may also contain sulphur or nitrogen. Additives are added after the refining processes to improve performance.
How do you produce synthetic oils?
Synthetic oils are created chemically in the laboratory but can also come from refined petroleum. Refining synthetic oils is a more complex process than for mineral oils because it involves modifying the structure of the hydrocarbon molecules. The purpose of this process is to retain only the best molecules and eventually produce the best oils.
There are also additives added in the process. Because of the composition and production complexity, synthetic oils are also considered high-end oils with higher performance compared to mineral oils.
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Semi-synthetic oils are a mixture of synthetic and mineral oils, but different semi-synthetic products may have different mix compositions. Some semi-synthetic products are composed of 30% synthetic oils. In some others, they contain just 1% of synthetic, although still labelled as semi-synthetic.
What Are Additives For?
Additives ensure that engine oils deliver the best performance. Both mineral and synthetic oils have additives added to them. There are also various kinds of additives, such as:
1. Oxidation inhibitor
Engine oils need replacement from time to time, as they will experience oxidation and become less effective. Oxidation inhibitor additives slow the oxidation process and improve an engine oil’s lifespan.
Detergent additives remove deposits and microparticles that from on surfaces while a vehicle is used.
Dispersant additives keep engines clean by preventing deposits and impurities from forming when an engine is running. They keep contaminants away and deposits are carried to the oil filter.
Detergent additives may generate foam on the surface of the oil. Foam prevents oil from working effectively to lubricate engine parts. Antifoam additives inhibit this process.
Anti-wear additives, also known as friction modifier additives, add a layer of solid oil that immediately lubricates the engine as soon as a vehicle is started and minimize friction between parts. Anti-wear additives are common in mineral oils.
6. Corrosion inhibitor
Engines are made of metal parts that are sensitive to rust. Corrosion inhibitor additives provide protection from rust for the engine.
7. Viscosity index modifiers
These additives enable engine oils to provide protection at both low and high temperatures. At the lowest temperatures, they keep the oil from freezing, allowing oil to lubricate the engine after a vehicle is started. Conversely, at high temperatures, viscosity index modifiers prevent oils from evaporating and maintain their viscosity to be able to work effectively.
Antifreeze additives help engine oils adapt to their environment by modifying the oil’s hardening temperature and can increase the fluidity of cold oil.
Engine oils may contain different mixture of additives and at different composition levels, depending on the oils’ specifications. In general, synthetic oils tend to have more additives compared to semi-synthetic or mineral oils. Regardless of the oil and additives type, always remember to use the oils suited for your engine as recommended by your vehicle’s manufacturer.