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I've always heard that you should change your oil every 3,000 miles (5,000 km). That little sticker you get on your windshield after an oil change agrees. Growing up, my parents told me the same thing.

I doubt that you need to change your oil that often to maintain a healthy engine. I suspect it's a ploy by the companies to increase profits.

Is it really necessary to change your oil that frequently to get the most life out of your vehicle?

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a rule of thumb doesnt apply in every situation. What if u need 10 years for this 3000 miles with ur hobby motor bike, what if one year...but 3000 sounds very low to me –  Werner Schmitt Jun 3 '11 at 18:54
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@Hairy: Absolutely. I've never heard of any standard production engines that need more frequent oil changes than 3000 miles, but it's certainly a false economy to do it less often than the manufacturer recommends. I think this talk of 'marketing tactics' is just tosh. The manufacturers don't get rich selling oil changes - they get rich by selling cars. And all other things being equal you'd buy the car with longer servicing intervals, so if anything they'd like to quote higher mileages between changes. –  FumbleFingers Jun 4 '11 at 0:33
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@FumbleFingers: I would not assume that an independent repair shop's interests were aligned with the manufacturers' or dealers' interests. Their interest is definitely in having customers come in more often. –  user1770 Jun 4 '11 at 1:29
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@FumbleFingers: I have never been to an oil change place that did not put 3000 miles on the sticker. –  stoj Jun 4 '11 at 6:13
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Let's see, my Honda's manuals mention it needs servicing every 20.000 kilometers. My previous car, a Ford, mentioned 15.000 kilometers. My father's old BMWs mentioned 25.000 kilometers.<br/> Every of those services includes an oil change, all of them are way longer than 4500 kilometers (3000 miles). <br/><br/> Can't find those service manuals online of course. Manufacturers include them with the car. If you visit a dealership they'll be able to order one for you. –  jwenting Jun 5 '11 at 4:30
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up vote 37 down vote accepted

No.

  • Wiki on this myth.
  • California's efforts to debunk this myth HERE

Synopsis: follow the manual's recommended oil change schedule, not the 3,000 mile recommendation that has become commonplace advice.

To translate that into some figures, I looked around for publicly available service manuals (just a few as I don't want to take all my time with this...):

  • 2002 Mazda Protege (LINK): 6mos or 7,500 miles, whichever comes first, Sec. 8-4
  • 2006 Volvo, all models (LINK): 7,500 miles
  • 2011 Ford Explorer (LINK): when light comes on (up to 10,000 miles or 1 year), pgs. 417, 420
  • 2008 Cadillac CTS (LINK): up to a year, Sec. 6-4
  • 2000 Oldsmobile Alero (LINK): whenever the light comes on, typically between 3,000-7,500 miles, but never longer than 7,500 miles or 1 year, Sec. 7-6

Edit: I thought it might be helpful to know typical driving distances per year, since that came up in the comments. They are listed HERE by the US Dept. of Transportation (current as of 4/2011). The average for all age groups across both genders is ~13,500/year. This would equate to 4-5 oil changes based on the 3,000 recommendation vs. 1-2 for the typical manufacturer's recommendations above.

As one last add-in, some in the comments brought up idle time. I don't know where that figures in. I'm assuming this question has to do with general use, however, not extreme cases of little/no usage.

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Type of Oil plays a huge role. With all-synthetic engine oil you could get away with much more than with regular oil. –  crasic Jun 3 '11 at 21:34
    
@crasic: Good point, though in my skimming did not see any mention of alternative schedules for oil maintenance when using synthetic. Thus, I'd still stick with the manufacturer's recommendations, regardless of the type, unless more information was provided about this particular issue. –  Hendy Jun 3 '11 at 22:01
    
from a speculative pov i would assume that current state of art in lubricating properties of oil could have increased drastically, as in last decades especially physial nano-analyisis methods progressed pretty much (scanning-probe microscopy, SEM) and the 3000 mile rule is more of a legend than a myth. Of course always look in ur manual. We have a pure engine oil company here in germany, so the change rate will directly define their revenue... –  Werner Schmitt Jun 4 '11 at 12:43
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@Werner: My earlier cars typically suggested 6000 miles for light use and 3000 miles for heavy use (and at least two-thirds of the driving around here counts as heavy), and mechanics may have gotten used to saying 3000 miles to people who insisted on the 6000. My current car tells me when it wants maintenance, but I don't know exactly how it figures it out. –  David Thornley Jun 5 '11 at 17:21
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@Chad: I'm open to this, but your experience from even an above-average number of vehicles is not yet representative of the statistical distribution. Ideally we'd need records from thousands of different makes/models in different climates and to know their service histories. In other words, substantiate that following the manufacturer's recommendations constitutes "not caring about the life of your car post 100k miles." Lastly, I don't know of any connection between the air conditioner longevity and oil changes -- the two are independent. –  Hendy Jun 6 '11 at 15:38
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There are really two factors to consider when determining an oil change interval. sludge and lubricity.

If you have an engine with a known small or easy to clog oil pick-up, keep that in mind.

If you oil start to turn to sludge it can accumulate in the valvetrain or clog the oil pick-up and end in engine failure or at least a lot of cleaning work.

Because synthetic oils damn near never sludge up the next is lubricity, an oil that has been through a high-revving 2.0l with a turbo will be more comprimised than one that had been through a low revving v-8.

Eventually an oil can lose the characteristics that make it lubricate properly.

The car may start fine and drive down the highway fine, but lets say you get stuck in the snow and give the engine and extended push to the floor to get in unstuck, the oil may not be able to keep up and boom.

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Welcome to Skeptics! Please provide some references to support your claims. –  Oddthinking Feb 20 at 22:04
    
there are far more factors, most having to do with contamination. Oil picks up all sort of residue (including metal particles), and needs to be changed when it gets too dirty. Your claim is overly simplified, and not substantiated by anything including maintenance procedures for commonly available cars. –  jwenting Feb 21 at 7:55
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