While we all buy motor oil for our car, we should really know which one to pick after thoroughly researching what’s best for the car. It’s not just the brand and the viscosity grade that we want, we should really be looking for what’s known as the API (American Petroleum Institute) donut symbol. This article examines the various factors that need to be assessed while picking out the motor oil for your car:

Certified Oil
It is a certificate provided by the American Petroleum Institute for testing the oil to meet the standards of API. You will find the symbol on every container of reputable motor oil. In addition to it there are two more characters “SL” which refers to a set of laboratory and engine tests, if it’s going to start with “S” it’s for gasoline engines. The most current service designation for gasoline engine is “SN’”. Now for diesel engine you will find a ”C” for the compression and commercials. So, the API donut symbol may be on the front of the bottle of oil or at the back. But what it tells us is few different things. First and foremost, in the middle of the symbol you will see the viscosity rates (5W-20 or 5W-30). Viscosity is very important. We have to make buy the correct viscosity grade not only to protect our engine but to make sure it can handle the climate outside that the car is operating in. The lower the number in front of ‘W’ the lower temperature in which it remains fluid. The bigger the difference between two numbers on our viscosity grade the wider the operating service range

Viscosity
There are two types of oils available the single viscosity oil and the multi viscosity oil. The lower the number the thinner the oil and more easily it flows. the higher the number the thicker the oil and the flow is very slow. Here’s a quick explanation of what these numbers appear to be when we see them in the front of oil cans, for example 5W-30. There are two sets of numbers here. 30 relates to how the oil performs at 100 degrees centigrade and 5W relates to how the oil performs when the oil is cool. It is an important component of oil change to understand.

Types of Oil
The premium conventional oil is preferred by most for the light- duty vehicles on road, particularly for lower temperature. Full synthetic oil is for high tech engines like Audi and Mercedes Benz which is superior and gives long lasting performance. These types of oils are very expensive and may not be required for your car engine. In fact, some car engines may not have certain features required for synthetic oil.