Motor Oil Ratings

motor oil ratings

Modern motor oils are a complex blend of petroleum products and additives that keep the engine running cleanly and efficiently. The motor oil ratings are done through a system that determines the proper use of the oil based on its viscosity, energy conservation qualities and types of additives.

Motor oil ratings are based on the following factors.

API Symbol

Check the back of any motor oil bottle to find out whether it meets API’s quality and performance standards. If it does, you will see the API symbol, which shows the motor oil's service category, viscosity ratings and energy conservation ratings.

Service Category

The service category shows the range of vehicles that can use a certain motor oil, depending on the car’s date of manufacture. Latest service categories for motor oil ratings are SN for vehicles manufactured in 2011, SM for 2005 - 2010 cars and SL for 2001 - 2004.

Viscosity

Choose the correct motor oil viscosity. Viscosity is the thickness of the oil at a given temperature. Also known as the oil weight, viscosity is designated as W, for example 20W. Multi-grade oils contain two weight values in their motor oil ratings; for example, 20W-50. This shows that the oil has a viscosity of 20W at low temperatures and a viscosity of 50W at normal engine temperature. You will find the proper oil viscosity rating on your car manual. The engine age and intended use can determine the best motor oil ratings for a car. In higher mileage cars, using a motor oil with a higher viscosity rating can improve oil pressure and reduce noise.

Energy Conserving

If a motor oil is energy efficient, the words Energy Conserving will be included in the API symbol.

Types of Additives

Motor oil ratings also vary according to the types of additives added. All modern motor oils contain additives, like anti-corrosion agents, anti-foaming agents, detergents and viscosity modifiers to improve performance. For example, detergent additives help clean carbon soot formed in internal combustion engines by suspending it in the motor oil until it is removed. So oil should be changed periodically as it becomes contaminated with the sludge formed by soot, acids, water, etc. that are created as the motor engine runs.

Once you understand these parameters, you will be able to choose the correct motor oil ratings for your car. You also need to know the difference between synthetic and mineral oils if you want to choose the right motor oil ratings. Although synthetic and mineral oils behave in a similar way, synthetic oils exhibit better heat-carrying characteristics, which improves engine wear.

ALL ABOUT AUTOMOTIVE TIPS