There are three types of engine oil available in market : Mineral oil, Synthetic oil and Semi synthetic oil. Here we will take a closer look what are the composites used in these engine oils. After discuss the role of additives for a superior engine oil performance.

Before we discuss, it is necessary to know that all engine oil made from base oil and additives. Although mineral, synthetic and semi-synthetic oils have different viscosities, uses and their compositions are different from each other.

Composition Of

Mineral Oil

Mineral engine oil is made from crude petroleum. Once it comes from the refinery, it goes through several refinery processes to remove other residues of petroleum. This contains mainly hydrocarbons (oxygenated or non-oxygenated). In addition mineral oil contains few nitrogen and sulphur compounds too. After completing the process, various additives are added to improve its performance.

important engine oil additives-engine oil manufacturer

Semi Synthetic Oil

Semi synthetic or part synthetic oils are a blend of both mineral and synthetic oils. They provide better performance, protection and fuel economy than mineral oil, but not as good as a full synthetic. semi-synthetic oil contains at the most 30% synthetic oil.

Fully Synthetic Oil

Synthetic oil is the most engineered lubricant to provide high engine efficiency. It can be chemically made in the laboratory. Purifying synthetic oils is a more complicated process than mineral oil. It modifies the composition of hydrocarbon molecules. In the process of obtaining oil, it ensured that only the best molecules are kept. Other additives are also added which increase its performance and prove it best in all engine oil range.

The main role of Additives used in Engine oil are :

Additives ensure the quality, performance and longevity of engine oils. Both mineral oils and artificial oils are added.

Antioxidant Additives (oxidation inhibitor additives)

Oxidation is the general attack on the weakest components of the base oil by oxygen in the air. Hydrocarbons usually react with oxygen to destroy them or their molecules break off. Through the anti-additive, the oxidation process is not completely stopped but slows down. That is why it is necessary to change the oil periodically. As a result the oxidation does not affect the parts of the engine.

Detergent Additives (keep the engine cleaner)

Detergent additive does two functions. First keep the engine’s hot metal parts clean and Second help neutralise the acid in the engine oil. Some detergents work by breaking down amazing oxygenated hydrocarbons that make the engine sludge in oil. In simple words, the main function of detergent additives is to remove deposits and micro particles that form on the surface while the engine is in motion.

Dispersant Additives

Dispersants are mainly found in engine oil with detergents to help keep engine clean and free of deposits. Dispersant additives keep all the deposits and impurities that form when the engine is running in suspension. The combination of detergent/dispersant additives allows more acid compounds to be neutralised and contaminant particles to stay suspended. In other words this additive perform their functions of neutralising acids and suspending contaminants. They will eventually exceed their capacity and make necessitate an oil change.

Anti-Foaming Additives

Anti-foaming removes foam from the surface of the engine. Adding detergent additive produces foam at the speed of the engine just like mixing detergent with water in the washing machine. But this foam becomes harmful to the engine and reduces the efficiency of the engine. Anti-foaming agents help reduce the tendency of the oil and its detergent additives to foam.

Foam in oil is basically air bubbles. And it can’t protect the moving parts of an engine. Therefore engine oil needs foaming inhibitors. Foam is also one reason why you shouldn’t overfill the oil. When the oil level is too high, the moving parts of the engine can whip the oil into foamy bubbles that can’t protect the engine parts.

Anti- Wear Additives (friction modifier additives)

Anti- wear additives add a layer of protective solid oil to prevent metal-to-metal contact. These additives reduce the friction and wear between engine parts while moving. It is mostly used in mineral oils. Anti-wear additives and extreme pressure agents form a large group of chemical additives. This group carry out their function of protecting metal surfaces during boundary lubrication through forming a protective film or barrier on the wear surfaces.

Corrosion Inhibitor Additives

As the name suggests, corrosion resistant additives prevent corrosion in parts of the engine.

Viscosity Index Modifiers

Viscosity can be said to be an important aspect in engine oil. Viscosity is a must when it comes to choosing engine oil. Viscosity index improvers are very large polymer additives that partially prevent the oil from being diluted (loss of viscosity) as the temperature increases. Good flow of oil at low temperatures keeps the viscosity index improving on egress, thereby reducing ware and increasing the performance of the oil. In addition, viscosity index improvers are used to obtain high-viscosity index hydraulic and gear oils at low temperatures to achieve improved start-up and lubrication.

Antifreeze Additives 

Antifreeze additive maintains engine oil flow even at low temperatures and prevents the oil from becoming thick. According to rule engine oil starts to become thick as the temperature goes down.


Hope, you have received satisfactory information about the key role of all important engine oil additives. This article provided main additives list added to engine oil  but this is not enough. There are still many other additives available in the market.