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How to choose the right engine oil?

Published Date - 9th Jan 2020



Engine oils cool, clean and protect your engine. For engines to perform to their best, selecting the right engine oil is crucial. 

Inevitably, we all want our car engines to run smoothly. However, not many understand that for an engine to run well, choosing the best engine oil for it is quintessential. If a wrong engine oil is fed to your engine, it will burn more fuel, increase emissions and interfere with your car’s warranty. 
Engine oils are like the blood for your engine, they circulate throughout the engine, allowing the pistons to slide smoothly in the engine cylinders hundreds of times per second. The engine oil also releases impurities contained in the engine circuit, reduces the friction between the metal parts and ensures your engine is properly lubricated. 

What you need to know while choosing an engine oil:

When you are looking out for an engine oil, be aware about which type of oil you need. There are two broad categories of engine oils, namely- synthetic or mineral oils. Mineral oils are the ones that come from petroleum products, synthetic oils are created with synthetic components, whereas semi-synthetic oils are a blend of mineral and synthetic oils. 

Mineral oils

Mineral oils are made of refined petroleum products. They are thicker in nature as compared to synthetic oils and semi-synthetic oils, making it best-suited for older vehicle models or engines without turbochargers. Their oxidation stability is low as compared to other engine oils, due to which frequent changes are required. Mineral oils are recommended for driving in temperate climates (that aren’t too extreme) and are more economical when you compare engine oil prices. 

Synthetic oils

Synthetic oils are obtained by mixing several synthetic components. They are designed for high-performance engines, making them a suitable option for auto racing. Better in quality, synthetic oils contain fewer impurities and can withstand high temperatures. There is more wait time between oil changes with synthetic oils, for both diesel and petrol engines. 

Semi- synthetic oils

Semi-synthetic oils are made of mineral and synthetic oils, offering the best of both worlds without incorporating their drawbacks. With a good price/quality ratio, the blend of mineral and synthetic oil gives it better protection and performance. The usage of semi-synthetic oils does not modify the frequency of oil changes.

Standards to keep in mind while choosing an engine oil:

When you are choosing an engine oil, keep a check on the standards of the product. Things to keep in mind about the standards are:

  • the type of engine the engine oil is designed for (diesel or petrol)
  • the performance levels
  • how well the oil meets the recommendations on the owner’s manual

There are three standards that are used to characterize engine oils:

The API standard

Established by the American Petroleum Institute, it classifies the product according to the dispersive power, protection against wear, oxidation, corrosion and detergents. There are two letters to determine the standard: 

S for Service (petrol engines)
C for Commercial (diesel engines)

The letter that follows the above letter indicates the engine oil’s performance. The “further” the letter is in the alphabet, the higher is the quality of the oil. So, a SF oil has lower performance as compared to a SR oil.
To know the standard required for your vehicle, see your vehicle owner’s manual or get advice from a professional.

The ACEA standard

This is the standard of the European Automobile Manufacturers' Association. It is a quality indicator that is determined by a letter and a number (For Eg: A1). The letter indicates the type of engine: 
A = Petrol engines
B = Diesel engines
C = Light engines compatible with catalysts
E = Heavy duty diesel engines

The number indicates the specific performances the oil must provide. 
ACEA 2016 defines 

  • 3 category combinations for petrol and diesel engines: A3/B3, A3/B4, A5/B5
  • 5 categories for vehicles with a pollution control device: C1, C2, C3, C4, C5
  • 4 categories for commercial vehicles and trucks E4, E6, E7, E9, of which two are for vehicles with a pollution control device: E6 and E9.

The SAE standard

Determined by the Society of Automotive Engineers, this standard describes the degree of engine oil viscosity. It is indicated on the front of the container: the 00w00 index.