Motor oil key proponent for well-being of auto's engine

OK, we had an arrangement. You'd change me every 3,000 miles or three months and in exchange, I'd keep critical parts of your precious vehicle's engine lubricated, cleaned and cooled. Here I am, however, dirty and old and still expected to perform. No way, Jose!

Although oil can't speak for itself, it's the engine's life-blood and changing it regularly is still the single most important thing to do to ensure the engine's long life.

Auto Service

• Performance Service Locator
• NASCAR Performance Network

• About the show
• TV Listings

What happens when oil ages and why does it need to be changed? With time, oil becomes contaminated by sources including dust, metallic shavings, condensation and even antifreeze. The additives in the oil that protect the engine break down, lose their effectiveness and can act as contaminants or corrosives.

When contaminants are present, they can stick to parts of the engine and act as abrasives, causing it to perform less efficiently. The oil lubricates poorly and is much less effective at cushioning the moving parts of the engine, which can increase friction. Ultimately, an engine that is not properly lubricated will wear prematurely and could seize up due to the friction and heat. Regular oil and filter changes can eliminate the contaminants and limit the effects they have on the engine.

Bottom line: oil change improves efficiency, fuel economy and dependability, and protects the engine. Not getting a regular oil change could cause the most problems for a vehicle, when compared to other maintenance issues.

So always follow your owner's manual for viscosity and grade of motor oil. Viscosity refers to the thickness or thinness of the oil. The viscosity of oil changes with temperatures. Oil thins when heated and thickens when cooled; therefore, having the proper viscosity grade for the climate and temperatures of your geographic location is very important.

Oil that does not flow well in cold temperatures will leave parts of the engine with no protection, while oil that burns off and becomes too fluid in high temperatures will also leave parts of the engine unprotected.

To find the right motor oil for your car and learn more about how to win a trip to the Nextel Cup Series Champions Week, visit www.mobil1.com.