Alright I am sure this has been discussed on here a lot before buuuut...why did/do they say 3000 miles OR 3 months? The 3 month is what I am wondering about, what happens to the oil after this amount of time if it doesn't have the miles on it? I understand the 3000 mile change does not really apply to modern cars or oil. I have a 1995 nissan that just hit its 3 month mark running QS Defy and a P1 filter but only has about 1600 miles on the oil. Thanks!
Why the 3 month?
- Thread starter zeke1985
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I think it is just a reflection of the fact the industry used to consider the average annual mileage to be 12,000.
It means the garages will get to make money on you every three months if you Do low miles and maybe every two months if you do a higher mileage.
It means the garages will get to make money on you every three months if you Do low miles and maybe every two months if you do a higher mileage.
Kestas
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They just assume you're a short tripper who never thoroughly warms up his car. This type of driving would result in all kinds of condensation and degrade the oil properties. If you instead do long drives infrequently, then this three month recommendation isn't for you, and you can go longer with your oil.
Just business so one can go to a local shop\dealer to pay for their service! But if you use Conventional oil like in this case or defy or good for a approx. 3K-5k oci. If you use full synthetic you can be clear for an 8K or more oci. The defy is SB so you'll be good. Besides depends on your driving if you drive hard cold starts and just drive constant well yeah replace the oil every 3K . I'm also running QSDefy and I'll be happy to change it at 3K fresh new oil with additives won't hurt no engine
Originally Posted By: zeke1985
..why did/do they say 3000 miles OR 3 months?
They like a regular infusion of your cash......
...plus they knew you would never buy every 1000 miles or 4 weeks.
..why did/do they say 3000 miles OR 3 months?
They like a regular infusion of your cash......
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It catches the "severe duty" case where it's largely short trips.
While the oil itself doesn't wear out, the additives do, and if you are driving short trips, then it's possible that you don't get the engine up to temp and to over-simplify, that can leave a "toxic soup" of acids, water, and unburnt hydrocarbons in your oil, ultimately depleting the additives meant to protect against such things.
So car makers specify not only a mileage component to the OCI, but also a time component.
The only way to really know if the oil is done after 3 months would be to perform a used oil analysis. But since replacement oil is probably cheaper than a used oil analysis, the most cost effective choice is to change the oil.
You might be able to make a case for 5K miles and/or 6 months and then do oil changes mid-spring and mid-fall.
While the oil itself doesn't wear out, the additives do, and if you are driving short trips, then it's possible that you don't get the engine up to temp and to over-simplify, that can leave a "toxic soup" of acids, water, and unburnt hydrocarbons in your oil, ultimately depleting the additives meant to protect against such things.
So car makers specify not only a mileage component to the OCI, but also a time component.
The only way to really know if the oil is done after 3 months would be to perform a used oil analysis. But since replacement oil is probably cheaper than a used oil analysis, the most cost effective choice is to change the oil.
You might be able to make a case for 5K miles and/or 6 months and then do oil changes mid-spring and mid-fall.
Whatever comes first. I do 6 months on dino or 8 months on syn for short trip OCI's. It would be only 4,000mi on the oil change.
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I have a Blackstone analysis kit ready to send off when I change the oil, so I am kinda looking for excuses..but I guess 3000 would be a good mark to change it and send in.
3 months/3,000 miles is overkill with modern engine oil. No major auto manufacturer (to my knowledge) recommends service intervals under 5,000 miles except in severe circumstances, and modern oils can last much longer than 3 months in service. The 'oil' industry justifies the ultra-short interval by saying that by recommending 3 month/3,000 mile intervals, their customers average closer to 4 months/4,500 miles between changes.
But even that is overkill in the vast majority of cars. With modern conventional motor oils, 6 months/5,000 miles should be NO problem.
But even that is overkill in the vast majority of cars. With modern conventional motor oils, 6 months/5,000 miles should be NO problem.
Originally Posted By: zeke1985
I am kinda looking for excuses..
I hear ya... I'm 4,000 miles into a 7,000 mile OCI and I'm ITCHING for an excuse, but it would be a BITOG sin to dump PU after only 4,000 miles ; )
Patience! Check all fluid levels, add 2 oz of top-off oil and then more patience!
I am kinda looking for excuses..
I hear ya... I'm 4,000 miles into a 7,000 mile OCI and I'm ITCHING for an excuse, but it would be a BITOG sin to dump PU after only 4,000 miles ; )
Patience! Check all fluid levels, add 2 oz of top-off oil and then more patience!
6 months here too. I drive maybe 2,000 to 2,500 miles in that time, at least half of it is very short trips mostly 2 miles round trip. My wife drives 5 miles a day back and forth to work 5 days a week, and we do a fair amount of short trips in her car too. I change the oil in my truck and her car every 6 months regardless of mileage.
Oil also used to suck big turds bac kin the day. SA-"SF" maybe was bad quality at any grade and had to be, until the 80s?
Originally Posted By: GearheadTool
Oil also used to suck big turds bac kin the day. SA-"SF" maybe was bad quality at any grade and had to be, until the 80s?
That's not my experience. Oil worked fine back in the day...back in the day, the oil was good quality, or my 1977 Oldsmobile would not have gone over 200,000 miles running on oil that performed as poorly as you just described. Shoot, I have an 81 year old car that's been run for decades on all that "awful" SA oil...and unlike other vehicles described in his forum, it hasn't been blown up or junked.
But an engine with a carburetor used to suffer from fuel contamination to a much greater degree than engines with FI do now...the super rich mixture would wash down the cylinder walls and changing oil at 3 months in sub zero weather was required because of all the time that engine spent running on full choke. When you did change the oil, it smelled strongly of gasoline (not a used oil analysis, but it was very noticeable).
For the OP, you don't need to change your oil until the mileage recommended in your OM...and maybe not even that soon if a used oil analysis shows it's holding up well...
Oil also used to suck big turds bac kin the day. SA-"SF" maybe was bad quality at any grade and had to be, until the 80s?
That's not my experience. Oil worked fine back in the day...back in the day, the oil was good quality, or my 1977 Oldsmobile would not have gone over 200,000 miles running on oil that performed as poorly as you just described. Shoot, I have an 81 year old car that's been run for decades on all that "awful" SA oil...and unlike other vehicles described in his forum, it hasn't been blown up or junked.
But an engine with a carburetor used to suffer from fuel contamination to a much greater degree than engines with FI do now...the super rich mixture would wash down the cylinder walls and changing oil at 3 months in sub zero weather was required because of all the time that engine spent running on full choke. When you did change the oil, it smelled strongly of gasoline (not a used oil analysis, but it was very noticeable).
For the OP, you don't need to change your oil until the mileage recommended in your OM...and maybe not even that soon if a used oil analysis shows it's holding up well...
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And before that, OCIs were around 1,500 miles.
And even less in the early days!
We are progressing.
And even less in the early days!
We are progressing.
My Packard service manual recommends every 500 miles...with a cylinder head removal every 1,000 to "de-carbon" the engine using a wire brush....followed by resetting the timing and "dressing" the points...
Yes, we are getting better...
Yes, we are getting better...
The owners manual for my Grand Caravan recommends a 3k OCI for stop and go driving. I am currently running Mobil 1 0w-20, so I might bump it out to 5k, but due to fuel and water dilution from the relatively short trips and rare highway miles, no more than that.
if you change your oil every 3 months or 3000 miles you are wasting your money and your oil ...Those days are long gone..maybe the oil change places want you to believe that 3 months 3000 miles is what you should be doing but even a lot of them dont say that anymore because it sounds like they just want more business and that is what they want...
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