Surely a lot of drivers have a vague sense that it is important to change engine oil every so often. Most might identify that it is bad for an engine to run low on oil. Or know that old, dirty oil could be a cause for concern. But why? What does motor oil do for your car? What if you wait too long between oil changes? Or use the wrong kind of oil?

The mission of motor oil inside your engine is a symphony of moving metal parts that work in concert to produce power. Pistons move up and down in their cylinders as they respond to bursts of energy during the combustion process. A series of lifters, rockers, and pushrods move with the camshaft to open and close up to three dozen valves to let air and fuel into the cylinders and exhaust out. The pistons pedal a heavy crankshaft that transmits torque to your transmission so your car can move. If it were not for motor oil, all of those metallic components would be scraping against one another. Motor oil serves as a thin film to lubricate those parts, reduce friction, and prevent too much heat from building up. You can imagine that motor oil needs to work pretty hard to do its job. And not just any old oil will do. For instance, each engine is designed to operate with a specific grade of motor oil. Grade (or weight) is a way of describing the viscosity of oil. (Viscosity is a liquid’s ability to resist flow - how thick or thin it is). Oil needs to be thick enough to coat those components, but thin enough to flow into all of the nooks and crannies inside your engine. When it comes to viscosity grades, the higher the number, the thicker the oil. Modern motor oil comes in multi-weight (multi-grade) formulas. You have seen them on store shelves: 10W-30, 5W-20, and the like. Those are products capable of acting like low-viscosity oil when cold (the “W” stands for winter) and high-viscosity oil when warmed up. See, oil tends to get thinner when it gets hot. Therefore, oil manufacturers include additives that combat that phenomenon. So, 5W-30 oil acts as 5-weight oil when cold to help you get your engine running, and 30-weight oil when your engine warms up. Motor oil quality also differs from one brand and product to the next. We are useing only Mobil1 Motor Oil, as the Manufacturer recommends.