Synthetic and regular oil are both lubricants used to protect moving engine parts and clean the engine. Synthetic oils are artificially made from compounds other than crude oil, while regular oil is made from crude oil.
Being made artificially, synthetic oil is more uniform than regular oil, having no contaminants and a uniform chemical structure. Regular oil may have impurities that inhibit its ability to protect against heat and friction.
Synthetic and regular oil function similarly, providing protection against engine wear and tear. However, synthetic is recommended in high performance and high-revving engines. In fact, on some brands like BMW and Saab, it is used from the factory.
Major oil companies offer both synthetic and regular oils in a variety of viscosities to serve different applications. A synthetic blend, which features regular oil mixed with synthetic oil, is a popular choice for drivers of high mileage vehicles.
Although synthetic and regular oil differ in their construction, they are fully compatible with each other. However, remember that some of the protection offered by synthetic oil is diminished, so change the oil sooner than you normally would.
The development of synthetic oils may eventually allow cars to operate without regular oil changes. While the purity of synthetics will allow this, users of conventional oils will continue to require oil changes every few thousand miles.
