So, it’s time to change your oil. You drain the oil, change the filter, and fill the crankcase with fresh oil, right? Yes, but there’s actually a lot of science behind what’s going on in your engine to keep it running for the long haul.

Above all, there’s the oil itself. These days, most, if not all motor oils the average user will use are multi-grade oils. In short, as motor oil heats up, it thins out. If the oil in a hot engine gets too thin, oil pressure drops and engine damage will eventually occur. Multi-grade oil includes substances known as viscosity index improvers. These allow a motor oil to retain thickness, or viscosity, at higher temperatures.

Motor oil isn’t all derived from petroleum, either. Many oils commonly available now are fully synthetic. These synthetic oils have proven to last longer and provide an engine better protection. Whatever oil you choose use, make sure that it matches your car’s manufacturer’s recommendations in regard to viscosity (there may be different options, based on the environmental conditions of where you live, and the season), API classification, and oil change interval. Some modern cars don’t even have a recommended oil change interval, but rather monitor the condition of the engine oil via the on board computer and alert you when the oil needs to be changed. Even if your car doesn’t have this technology, don’t rely on the old 3,000 mile rule of thumb for changing your oil. The correct interval is that recommended by the car’s manufacturer, and is often higher than 3,000 miles. In effect, paying attention to the manufacturer’s recommendations here will save you time and money.

In some cases, as with some European cars, engines have such high requirements for lubrication that certain manufacturers have needed to develop their own specifications and their own oil blends. There may be aftermarket oils that meet those requirements, but be sure to make sure the oil meets those requirements, or once again, you may cause engine damage by using the wrong oil.

In addition to synthetics, there are now recycled oils available. As an engine uses oil, the oil picks up dirt and contaminants. But, contrary to popular belief, the base oil actually does not degrade or break down. Now, used oil is being reclaimed, the contaminants being filtered out, and sometimes blended with new base oils before being resold.

The motor oil industry is constantly changing, developing, and engineering new products. On top of recycled options, the industry is constantly researching and experimenting with developing oil from new sources. One possible future product is engine oil derived from recycled plastic. But, given what’s available even today, it’s hard to say what you’ll be putting in your engine tomorrow.