I've been reading this site (and simmilar ones) a lot, and I noticed a lot of people (mainly from USA i think) who mention 3000-6000 mile intervals for oil changes.

I'm from Europe, and driving a Korean petrol car, and my service/oil change interval is 20.000km (~12k miles). A lot of diesels have even longer ones (30kkm - 18k mi). These are the intervals specified in original, manufacturer's service booklet.

Why are the numbers so different?

1 Answer 1


Simple , Ignorance on part of the people.

The 3000-6000 mile oil change trend in the US is actually not necessary.

In the old days the cars were not as refined and the oils were also not that good so you needed a lot of oil changes for your engine to be healthy.

However in the modern times especially with the advent of fully Synthetic oils the frequency for oil changes have shot up to 15k miles.

Most people don't realise this and end up shelling a lot of money on pointless oil changes(Especially in the US).

Other reason as to why I think people do it is that it gives a chance to the mechanic to look for issues with the car.

One major side effect of frequent oil changes is that the waste oil polluting the enviornment which can be easily prevented.

Bottom line is that you "DO NOT" need to change oil at every 5k or 6k miles.

  • 2
    Several points: 1) Change the oil as often as the manufacturer states to maintain the warranty. If you don't, the cost of part replacement is upon the owner. 2) Most engine oil is recycled. A lot less pollution going on due to oil changes. 3) Oil life indicators have done a lot for engine oil longevity. For the car to calculate the life is probably one of the best factors in realizing when the oil is due for change rather than relying on an arbitrary number (like the general 3k miles). 4) Changing oil at a 3k interval is not going to harm the car one little bit, regardless. Jun 16, 2015 at 16:43
  • One other thought: A lot of newer vehicles have a larger oil reserve (takes 8-9 quarts to change the oil). This allows it to last longer, which increases the change interval. Jun 16, 2015 at 18:22
  • Changing the oil @ever 3k interval is sure going to harm the pocket :-)
    – Shobin P
    Jun 17, 2015 at 10:41
  • 1
    Another factor is that shops which specialize in oil changes continue to promote more frequent changes because it's profitable for them.
    – barbecue
    Oct 21, 2016 at 16:48
  • (barbecue) a shop specializing in oil changes sounds weird to me, maybe because in India no such shops exists and @Pᴀᴜʟsᴛᴇʀ2 unfortunately very few shops actually takes any steps to recycle the oil so impact on environment is far greater here. anyways changing your oil sooner will never harm your engine.
    – Nilabja
    Nov 6, 2017 at 6:24

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