You regularly get your car’s oil changed, but do you ever wonder why?

Sometimes referred to as a car’s “lifeblood,” oil keeps the engine clean and lubricates its parts at the same time. Oil also transfers heat away from the combustion cycle. Sound complicated? It’s really not.

A car’s engine is full of metal surfaces that move at extremely high speeds. If these parts didn’t have oil between them, they would rub together and the friction would tear them apart. At the same time, the oil is keeping the surfaces apart, it is also transferring heat away.

OK, so that makes sense, but how can something as dirty as oil keep a car’s engine clean. It’s actually pretty cool. An engine operates by combustion. In the simplest terms, a tiny explosion occurs, causing a piston to go up and down. This part of the process and many others produce many by-products. These by-products include silicon oxide and acids, which can be harmful to the engine’s parts. This is where the cleaning part comes in. Oil holds these contaminates in suspension and keeps them from forming on the engine.

You hear the term viscosity associated with oil. Viscosity is defined as the property of a fluid that resists the force to cause the fluid to flow. Basically that means how much pressure can it withstand before it moves. When you see a container of oil marked SAE 10W40, what does it mean? First, the SAE stands for The Society of Automotive Engineers. The numbers tell you about the oil’s viscosity.

The higher the number, the more resistant to flow; the lower the number, the easier it flows. Oil marked 10W40 means that it can flow at a 10 viscosity grade when it’s cold and a 40 viscosity grade when it’s hot, with the W meaning winter.

Keep this in mind: oil gets thicker when it’s cold and thinner when it’s hot. When it’s cold (which makes oil thicker), it must remain thin enough to flow (10); when it’s hot (which makes oil thinner), it must be able to remain thick enough to do its job (40). In essence, you’re getting oil that can work all year around.

With this in mind, let’s say that you live where it gets really cold in the winter and stays mild in the summer. Then an SAE 5W30 oil might be the best for your car… make sense?

As for how often to get your oil changed… the debate rages on. The safest bet is to go by what the owner’s manual says.

Now you can see why it’s important to have your oil changed. It’s got a lot to do and after a while it will lose the ability work properly. The next time someone says “I need to get my oil changed,” you can say, “Let me tell you a little something about oil.”

Copy the Story Link