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Comment by milesskorpen | Hacker News Reader

Oil changes every ~6 months = $500+ on their own over six years

You'd do an oil change after 1000 miles?

There used to be recommendations to change oil for time as well as mileage. Has that changed? Also, not all driving is equal. Stop and go driving in the city is many times more wearing than highway driving.

It's gotten more lenient.

Lots of newer cars are coming out with 7.5k/6 month oil changes (realistically, that will go well beyond 6 months). Even some cars are coming out with 15k/12 month oil changes.

Definitely longer than the 3k/3 month oil changes of the past.

My Toyota Camry is now 10K/12 months oil change interval.

you change oil every ~6K miles, not 6 months.

Most manufacturers recommend 6-10k miles or 6 months, whatever is sooner.

IIRC, the reasoning is mostly about failures of parts/screws involved in the maintenance.

The labor required to tap a seized lug or corroded filter that gets stuck is a multiple of the cost of oil change. There may be temperature related reasons as well, but getting facts about a topic that fuels passions as much as motor oil is difficult.

I clearly stoked that passion based on the wide variety of reasons one should or should not change based on time, distance or otherwise. And no two reasons appear to be the same (o;

With some egregious appealing to authority.. I will say that as someone who performs oil changes on our daily driver Honda Element, a 1987 VW camper (when it both had the original engine and the new ford Zetec engine it currently runs on) as well as my 2001 BMW motorcycle, 1970s cub cadet lawn tractor and the Harbor Freight engine I transplanted on to the snowblower...

I have never once encountered a ceased sump plug or stuck oil filter. Ever.

I'm not saying the monkey at Zippy-lubers wont strip a plug because he was busy texting his girlfriend at the same time. But I've pulled parts of engines that hadn't see action for decades. This is not a reason for a 6 month schedule

The only advice I've seen, and oddly enough it's not been mentioned in this thread so tack it onto the list of oil change folklore, is acidic buildup due to oxidization and the timeframe on that is roughly a year.

I have never ever seen a filter corrode on something that wasn't literally sitting in a field for 20 years. Oil plugs basically never corrode either, if they fail it is almost always due to some mouth breather at the quicky lube using the air wrench on it and putting in one too many ugga duggas or somehow cross threading it.

IMHO 6 months is much too short of a minimum interval for modern oil. 12 months is a much more reasonable interval.

No, you change it at least every 6 months, more often if crossing the mileage threshold. There are several kinds of oil degradation occuring, one of them is elevated in cars that don't drive much, or only drive short trips. Read an owners manual - you'll see words like 'every 5,000 miles but no more than 6 months'.

There used to be recommendations to change oil for time as well as mileage. Has that changed?

It hasn't changed, it's just that there's misinformation abound.

The standard recommendation is every 3000 miles for non-synthetic, which is very very wrong (too frequent) and serves to enrich quick lube shops at the cost of the environment. Folks with newer cars should NOT follow this recommendation [1], but instead refer to their car owner's manual.

[1] https://www.scientificamerican.com/article/oil-change-truths...

With synthetic oil you are far less often required to change oil due to time. Oil just doesn't degrade like it used to.

Also, oil changes every 6 months was mainly used as an appropriate time frame in case someone forgot to watch their mileage, with an average of ~14k miles driven in a vehicle a year that averages an oil change every ~7k.

No, the 6 months recommendation is due to absorbed water vapor causing gelling and sludge. It's specifically targeted at vehicles that aren't driven often, or only take short trips. In these vehicles the inevitably absorbed water is not driven off by engine heat often enough and they become fouled due to sludge.

The mileage based change intervals are about two kinds of degredation, shear (loss of viscosity), and Ph (exhaustion of wear additives). Shear may be improved by synthetics but additive depletion is not, although it is uncommon to run oil long enough for that to become critical.

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