Urban Legends About Motor Oil

Even though Edmunds has definitively debunked the myth of the 3,000-mile oil change, we keep hearing wildly contradictory information about engine oil, what type to use and how often to change it. So we issued a call for oil myths, legends and lies, and gathered up a list of the top puzzlers. We then put these questions to the experts and came up with some interesting answers. Here’s a list of seven oil myths and realities to guide you through this murky subject.

1. Change your oil every 3,000 miles or three months — whichever comes first. We’ve said it before and we’ll say it again: This is a myth for the vast majority of modern cars. The 3,000-mile oil change is the credo of the quick-oil change industry and dealership service departments, designed to regularly get you into the service bay. Experts agree that the oil in today’s cars should be changed at the designated intervals in the owner’s manual or when the car’s oil life monitor light appears. (The average interval for 2010 cars is around 7,800 miles.) Oil experts and car manufacturers say that oil chemistry and engine technology have evolved tremendously in recent years, extending oil change intervals.

2. Change your oil before a long road trip. There is some truth to this. It’s definitely a good idea to look your car over before long drives, says Dan Edmunds, director of vehicle testing for Edmunds.com. However, if the oil change interval is not scheduled to occur during the trip, it is not necessary to change it preemptively. If the oil change interval would arrive during the trip, then it’s a good idea to change it before you leave. But Edmunds cautions that having service work performed just before a trip carries a risk. He was once driving miles from anywhere when a car passed him, trailing oil. It turned out the owner had just had her car’s oil changed, and the shop had not properly tightened the drain plug. It had vibrated out. Edmunds suggests scheduling a service visit for about a week before leaving on a big trip, just to make sure everything is working properly before you hit the road. Here’s more information about when to change your oil.

3. Nearly all cars should be serviced under the “severe” maintenance schedule. This oft-cited rule is a myth the quick oil-change industry (including Jiffy Lube) uses to bolster more-frequent-than-necessary oil changes, experts tell Edmunds.com. When manufacturers say “severe,” they mean situations in which vehicles pull heavy trailers, or cars race on closed tracks. It also applies to taxis or emergency-response vehicles that can idle for hours at a time. Just plain old stop-and-go traffic doesn’t automatically bump people into the severe schedule. For further proof, consider this: A number of automakers, including Ford and GM, contacted Edmunds data editors to request that the maintenance section of Edmunds’ site substitute the normal maintenance schedule for the severe schedule that had been displayed. If your car has an oil life monitoring system the severe-versus-normal question is moot.