How often should I really change my motor oil?

How long should you go between oil changes? It's hard to get two experts to agree on the question. But most concur that changing your oil every 5000 kilometers is caretaking overkill. 

Do you change your oil every 5000 kilometers? The majority of drivers on the road have been bombarded by advertising that recommends changing their car's oil every 5000 kilometers, but the truth is that interval is no longer really necessary.

Yes, engine oil does get dirty, and when that happens, it can clog engine parts, but if you're driving a car that's less than five years old, you're probably wasting money - and oil - if you change it as frequently as that. Yes, knowing when to change oil is not as simple as some ad campaigns would have you believe.

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Changing the oil in your car every 5000 kilometers was necessary in the 1970s, when most cars used 10W-40 oil, which tended to wear out within about 5000 kilometers. Thanks to improvements in high-quality lubricants and tighter tolerances in the assembly of automotive engines, the 5000 kilometers baseline simply does not apply to many cars on the road today; in fact, automakers now recommend you change oil at 10,000, 15,000 or even as high as 25,000 kilometers for newer models under ideal driving conditions.

For example, Toyota recommends you change oil at 8000 kilometers for a 2005 Tacoma pickup, Honda recommends 12,000 kilometers for its 2002 Odyssey, General Motors suggests 12,000 kilometers for its 2007 Chevrolet Malibu, and Ford recommends 17,000 kilometers for its 2011 Fiesta. A 2008 Porsche Boxster can go almost 20,000 kilometers between changes, and a 2010 BMW 3 Series can go up to 25,000 before you change oil under ideal conditions.

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With this kind of complexity, it's easy for consumers to be confused.

What Is Considered Severe Use?

Severe use involves extensive idling or driving frequently in stop-and-go traffic; operating in cold temperatures below 10 degrees or extreme temperatures above 90 degrees; extreme humidity; repeated short-distance trips of less than five miles; towing a trailer or hauling heavy materials; or using E85 fuel more than 50 percent of the time. If you do drive in any one of these conditions in a typical week, you are driving in severe conditions, and may need to change oil more often.

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What Happens if you Don't Change Oil in Your Car?

As Alina Tugend of the New York Times says, "It just gets dirtier and dirtier. It's like mopping the floor with a bucket of water and detergent. The water starts out clean, but the more you use it, the filthier it gets. Eventually, you're making the floor dirtier if you don't change the water." Dirty oil no longer lubricates properly, increasing friction, operating temperature, and causing the engine to wear faster.

Do You Know When to Change Oil?

Your car's owner's manual will tell you how often you need to change your oil. If you drive a newer model, the car may just tell you when you need to change your oil. Since 2003, General Motors has equipped nearly its entire North American lineup with the GM Oil Life System; in fact, since the 2010 model year, nearly half of American carmakers now offer Oil Life Monitoring Systems to tell drivers when their car actually needs its oil changed, including Acura, BMW, General Motors, Honda, Mercedes-Benz, and Mini. These Oil Life Monitoring systems automatically monitor engine characteristics, driving habits, cold starts, short-distance trips, and the climate in which the vehicle is operated, and then notify the driver when it is time to get an engine oil change with an signal on the dash indicating it's time for service.

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If you are an extremely low-mileage driver you should change oil at least once a year. Otherwise, if your vehicle is equipped with an oil life monitoring system, you can trust the info/alert in your dashboard to tell you more accurately when you need a change. Don't have an Oil Life Monitoring System? Consult your owner's manual, your auto manufacturer's official website, or authorized dealer for more information. Curious about your car right now but don't have an owner's manual handy? You can find suggested oil change intervals for many makes and models all the way back to the 2000 model year on the nifty widget at www.checkyournumber.org.

Tired Of Changing Your Oil Every 5000 Kilometers?

Then trade in that beat-up 1970's jalopy for something newer! Consider these new models that boast 17,000 to 25,000 intervals:

     —All 2012 Audi models suggest you change oil at 17,000 kilometers

     —All 2012 BMW models suggest you change oil at 25,000 kilometers

     —2012 Ford Fiesta, Flex, Focus, and Mustang models suggest you change oil at 17,000 kilometers

     —All 2012 Jaguar models suggest you change oil at 17,000 kilometers

     —2012 Lincoln MKT and MKX models suggest you change oil at 17,000 kilometers

     —All 2012 Mercedes-Benz models suggest you change oil at 20,000 kilometers

     —All 2012 Mini Cooper models suggest you change oil at 20,000 kilometers

     —All 2012 Porsche models suggest you change oil at 17,000 kilometers, though some can go as far as 20,000 kilometers between oil changes

     —Nearly all 2012 Toyota models go 17,000 kilometers between oil changes

     —All Volkswagen models can go 17,000 kilometers between oil changes

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