The Slick Truth on Synthetic Oil
So what's the difference? Synthetic oil is produced in a lab, which means the only stuff in it is what they put in it. Despite the high-tech refining of crude oil, there are still contaminants in the oil that can build up and eventually damage an engine. Changing your oil and filter removes any loose particles that form, but often the build-up occurs in an isolated area of your engine, usually where it gets really, really hot. This build up can clog oil passages and valves, which can eventually lead to reduced engine life.
There are also ecological benefits to using synthetic oil. Its viscosity (ability to lubricate) stays higher than mined oil at high temperatures, enough to even affect your gas mileage. Since it breaks down much more slowly than petroleum-based oil, you can greatly extend the time between oil changes. One truck driver drove his semi 409,000 miles on synthetic without changing the oil! Think of how much less oil would have to be collected and recycled if we used half as much every year.
The bottom line is synthetic oils are an easy choice. The extra bucks you spend for an oil change will be returned in no time.