For non-synthetic oil, how long can you go without changing the oil if you regularly only use a vehicle a couple times per month, for 30 miles per drive?

That's a total of only 1000-1500 miles/year, but the vehicle is consistently driven once every 1-3 weeks.

Evidence-based answers will be appreciated.

There is a similar question on this site, but I am interested in answers for much lower levels of annual mileage than that question specified. The mileage specified in that question is within normal oil change intervals for some vehicles, but to my knowledge, 1000-1500 annual miles is below any manufacturer's oil change interval. Thanks!

  • I would suggest you to change oil every 6 months\1500 miles if riding on good roads, less traffic or 1200 miles if you live in terrible traffic and dirt roads. no matter you use it or not.
    – Sakthivel
    Aug 13 '15 at 6:55
  • Thanks, but I've honestly never seen anything recommending oil changes after just 1,200-1,500 miles. More and more people are saying 6,000-12,000 miles with modern oils and that anything less is basically a scam by oil changing outfits (and a huge waste of oil). But I haven't been able to find data for what is appropriate when annual mileage is just 1,000-1,500 miles. Aug 13 '15 at 8:36
  • Your service book probably says 10 000 miles OR once a year. I like to chop those in half (or in thirds now that I have a high-maintenance car). So every 4 to 6 months, regardless of distance traveled. Aug 13 '15 at 10:22
  • People recommending you change your oil every 6-12K are assuming you drive it regularly. I had a neighbor who was the stereotypical "little old lady who only drove to church on Sundays". After her husband passed away I offered to give her car a tune-up and was shocked to see the condition of her oil. It looked like heavily-creamed coffee. Driving 30 miles will probably heat the oil sufficiently to drive off the moisture, but I'd check it every 3-4 months. Consider flushing your brakes, as that fluid absorbs water too.
    – TMN
    Sep 29 '15 at 19:49
  • @TMN Thanks. Her oil absorbed water? I didn't that was possible. Sep 29 '15 at 20:50

As mentioned in the answers in the linked question, the various additives in the oil break down over time, so the limit isn't just the number of miles done. Quite often your service interval will be listed as "X miles or Y time, whichever is the soonest" for this exact reason.

In your case, I think I'd do it once a year, but that's just my opinion without any scientific backup...

Bear in mind also that other parts will suffer from not being used, just as much as they would from over-use. For example, brake discs will rust while the vehicle is sitting, and so will cause more wear to the pads when restarted, so they won't last as many miles as in a regularly used car. You'll also need to keep an eye on rubber components (hoses, belts and tyres), as they will begin to perish long before their normal replacement mileages.

  • Thanks! Your answer is the one I want to believe... I'm hoping someone can find some sort of supporting evidence. Aug 13 '15 at 19:33

For non-synthetic, I think the rule of thumb is to change the oil twice a year at bare minimum - once in the spring, once in the fall.

The idea is that after six months, the oil (and the detergents in it) break down and can no longer do their jobs properly, regardless of mileage.

However, I'm only saying six months because that's what people older than me have always said. You could always get your old oil analysed (or do it yourself) after a change to see how much life is left in it after six months.

  • I've heard that rule of thumb and also one that says "once per year". Have you found any scientific evidence or testing for either? Aug 13 '15 at 2:58
  • Can't say I have, but I also haven't looked very hard. @RockPaperLizard - Addendum: I think all over the internet you can find people saying "I analyzed my oil and we found that you should change at least every _____," but at the end of the day, oil changes are cheap insurance, so in my car I don't drive often, I do twice a year. Unfortunately, that doesn't offer much in the way of an answer, but there it is.
    – zhang
    Aug 13 '15 at 3:34
  • @RockPaperLizard once a year is too long. In my practical experience 6 month is good period.
    – Sakthivel
    Aug 13 '15 at 6:57

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