When to use High Mileage Oil?

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I would like to understand when and why it would be a good decision to start using high mileage oil instead of non high mileage oil. This would be for all types of motor oil: synthetic, conventional, and synthetic blend.
What additive package elements are used to make an oil a high mileage oil?
If my vehicle is mainly used as a commuter (work) vehicle, at what mileage should I start to consider high mileage oil?
Should high mileage oils be used or not used in high performance engines?
Are there any risks using synthetic high mileage oil for extended oil changes( 10k miles)?
 
Synthetic is always better IMHO. Unless you ask some of the hi-thrift folks on this site.
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High milage oils have more additives to help the seals stay effective. You may never need hmo if the seals don't leak. (Little or no oil puddles underneath where you park.) I believe the age of the vehicle would determine the need for hmo more so than the miles. Extended oil changes should not be a problem with hmo synthetic any more than any good synthetic.
 
StevieBoy is right about the seals issue. High Mileage oils mainly have a little extra seal conditioners to keep seals from getting too brittle with age.
Thats about it, and a lot of marketing of course, but High Mileage oils are for real.

Mobil recently added the Mobil 1 Extended Performance High Mileage oil to their product line, and its good for 1 year or 15,000 miles, to answer your question, ddhmax1973, about going a long time between changes. That oil should do it, since their EP line has always had some PAO and pretty good anti-oxidants in it to support longer intervals.

I did see a video a while back from Valvoline's (MaxLife High Mileage oil) tech labs where they did say that "seal conditioners" were the main point, but they also load up their MaxLife oils with some other goodies. My guess is the extra goodies don't amount to much over non-HM oils, but the seal conditioning is decent.

Its my opinion that you can make any non-HM oil an "HM" oil by adding half a bottle of LiquiMoly Motor Oil Saver (amazon or NAPAautoparts), a good seal conditioner to tweak the formula slightly.

What miles to start using it? 75,000 miles is recommended. Its not a bad guess. Valvoline did say they picked that for their MaxLife products because they observed seals starting to get brittle about then.
 
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In all honesty, at least the way I see it, a person could start using High Mileage oil from the very start, and see a benefit. If the extra additives in the HMO help to condition the seals and keep them from getting brittle, wouldn't they conceivably provide that benefit even earlier and help the seals that much more?

It would be one thing if the HM oils were more expensive than just plain conventional, but really, they're not... okay, maybe a dollar or two per jug, but that's small potatoes compared to the overall price.

IMHO, worth it.
 
I use HM oil and not for the seal conditioners. Although it can't hurt. I replace oil seals that go bad. I use HM oil because the ones I use are ACEA A3 which is what my old junks need. The oils today are great for newer vehicles but not so for older ones. ILSAC oils are especially bad for old engines. I have tried every brand and spec oil in my old junks and they run the best on the A3 (HM) oil. They ran OK on ILSAC oils, just better on A3. Smoother, quieter and even better gas mileage, which I watch very closely. I'm not a fan of HDEO oils because I'm pleased the results of the HM oils. I'm also not a fan of oil additives.
 
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My 30 year old 4Runner doesn't use or leak oil, has been serviced at 3,000-5,000 intervals with primary conventional oils. Max Life is great oil and produces good UOA but I'm not sure that there is a mileage or age that it's required or desired. I'm motoring along with over 337,250 miles on plain old conventional and not leaking a drop.
 
Yeah FlyNavy I bet the seal leaking may well be due to oil that gets acidic and tears up the seals. By your typical regimen that oil never got acidic therefore it has not developed a leak. Just like my Altima 3.5 VQ with 234k miles.

There's nothing g wrong with high mileage oils. I have run Valvoline Maxlife Full Synthetic a time or two. I liked it quite a lot. My car runs very quiet on it. Some VQ motors have a valvetrain tick. With Valvoline Maxlife Full Synthetic is was totally quiet. There are other oils that have done just about as well as the VMFS.
 
If it ain't broke why fix it?? If the vehicle is not consuming oil or seeping oil IMO there is absolutely no reason to switch to a HM oil.
 
When you do have a leaky engine, HM is amazing at sealing up those leaks.

However, if you ever go back to non HM oil, it'll probably start leaking again. I don't think HM actually restores or repairs anything, it just makes your seals bloat a bit to keep everything a bit more sealed up. Everyone says its not harmful though but I would only use it as a cheap fix for a leaky engine that isn't worth rebuilding.
 
Originally Posted By: FlyPenFly
When you do have a leaky engine, HM is amazing at sealing up those leaks. However, if you ever go back to non HM oil, it'll probably start leaking again. I don't think HM actually restores or repairs anything, it just makes your seals bloat a bit to keep everything a bit more sealed up. Everyone says its not harmful though but I would only use it as a cheap fix for a leaky engine that isn't worth rebuilding.


You're confusing "seal sweller" chemicals for "seal conditioners". For example, Valvoline Maxlife Full Synthetic is dexos1 qualified, meaning they test that High Mileage oil against about 10 different seal materials to make sure it doesn't swell or shrink the seals much. That's an actual test in SN and many other oil specs too. Conclusion: No, its a myth that HM oils will "swell" your seals excessively.
 
A few years ago the high mileage oils had higher detergents and zddp.. but the recent voas i have seen they are cutting back.

In a nutshell high mileage oils should have high detergents to get rid of varnish and sludge and prevent more with looser tolerances and blowby. ZDDP for extra cushion against wear doesnt hurt either.

In todays time the 5w40 HDEOs have just about everything you need to keep an older engine clean...but high mileage oils arent what they used to be IMHO.
 
Originally Posted By: oil_film_movies
Originally Posted By: FlyPenFly
When you do have a leaky engine, HM is amazing at sealing up those leaks. However, if you ever go back to non HM oil, it'll probably start leaking again. I don't think HM actually restores or repairs anything, it just makes your seals bloat a bit to keep everything a bit more sealed up. Everyone says its not harmful though but I would only use it as a cheap fix for a leaky engine that isn't worth rebuilding.


You're confusing "seal sweller" chemicals for "seal conditioners". For example, Valvoline Maxlife Full Synthetic is dexos1 qualified, meaning they test that High Mileage oil against about 10 different seal materials to make sure it doesn't swell or shrink the seals much. That's an actual test in SN and many other oil specs too. Conclusion: No, its a myth that HM oils will "swell" your seals excessively.


Seal conditioner is just a more politically correct version of seal swell agents , I don't differentiate between the two.

Ive also seen Mobil1 hm oil, soften and swell valve cover gaskets( and begin leaks) and oil filter gaskets that are near gooey and bloated on removal, to where the gasket just pops out of the oil filter upon removal. Some motors its not an issue, others you may have just created a leak.

Seal conditioners = soften and Bloating, should be expected
 
I would think the "when" would be vehicle dependent. I have just began using a HM oil in a '97 Tacoma (3.4l v6) with 235k miles. Reason for me is weeping valve cover gaskets, which seems to be not too uncommon on this engine. Gaskets have been replaced once and I likely will again one day but the weeping is so slight I wanted to see if a HM oil with extra seal conditioner would be beneficial. If I did not see a possible benefit of a HM oil I would use a different version.

Also, the Mobil 1 HM oil I am using is a little heavier than the standard Mobil 1 with HTHS of 3.5 vs 3.0 and Vis@100C of 12.1 vs 10.1 despite both being 10w-30. I would think some differences between HM vs standard will be brand dependent.
 
Originally Posted By: oil_film_movies
Originally Posted By: FlyPenFly
When you do have a leaky engine, HM is amazing at sealing up those leaks. However, if you ever go back to non HM oil, it'll probably start leaking again. I don't think HM actually restores or repairs anything, it just makes your seals bloat a bit to keep everything a bit more sealed up. Everyone says its not harmful though but I would only use it as a cheap fix for a leaky engine that isn't worth rebuilding.


You're confusing "seal sweller" chemicals for "seal conditioners". For example, Valvoline Maxlife Full Synthetic is dexos1 qualified, meaning they test that High Mileage oil against about 10 different seal materials to make sure it doesn't swell or shrink the seals much. That's an actual test in SN and many other oil specs too. Conclusion: No, its a myth that HM oils will "swell" your seals excessively.


So if it's "conditioning" the seals... what do you think that means? Why do leaky engines start leaking again without HM oil? I've directly seen leaky engines stop leaking then start leaking again when switched back to normal oi.
 
I'd only use a high mileage oil in an engine with oil consumption or leaking problems, it may seem liek snake oil but my experience with for example Valvolien Maxlife is it really does slow down leaks and consumption.
 
Originally Posted By: Mackelroy
Originally Posted By: oil_film_movies
Originally Posted By: FlyPenFly
When you do have a leaky engine, HM is amazing at sealing up those leaks. However, if you ever go back to non HM oil, it'll probably start leaking again. I don't think HM actually restores or repairs anything, it just makes your seals bloat a bit to keep everything a bit more sealed up. Everyone says its not harmful though but I would only use it as a cheap fix for a leaky engine that isn't worth rebuilding.


You're confusing "seal sweller" chemicals for "seal conditioners". For example, Valvoline Maxlife Full Synthetic is dexos1 qualified, meaning they test that High Mileage oil against about 10 different seal materials to make sure it doesn't swell or shrink the seals much. That's an actual test in SN and many other oil specs too. Conclusion: No, its a myth that HM oils will "swell" your seals excessively.


Seal conditioner is just a more politically correct version of seal swell agents , I don't differentiate between the two.

Ive also seen Mobil1 hm oil, soften and swell valve cover gaskets( and begin leaks) and oil filter gaskets that are near gooey and bloated on removal, to where the gasket just pops out of the oil filter upon removal. Some motors its not an issue, others you may have just created a leak.

Seal conditioners = soften and Bloating, should be expected


You have any other examples or UOAs about this and what vehicle/generation/engine type? I read a lot of people commenting this but dont explain real world examples or even go based on what other people say. Not to mention which brand and type of HM oils they used. Not calling you a liar but it gets tiring to have to go through pages and pages on a topic that really gets no where but are filled with no real world facts/info. Just another comment that would get answered another few pages down the road and that's maybe so. I'm still learning about this myself as I have a 2AZ-FE on a 2007 vehicle that may be consuming oil.
 
Originally Posted By: crazy_raccoon
Mackelroy said:
oil_film_movies said:
FlyPenFly said:
When you do have a leaky engine, HM is amazing at sealing up those leaks. However, if you ever go back to non HM oil, it'll probably start leaking again. I don't think HM actually restores or repairs anything, it

You have any other examples or UOAs about this and what vehicle/generation/engine type? I read a lot of people commenting this but dont explain real world examples or even go based on what other people say. Not to mention which brand and type of HM oils they used. Not calling you a liar but it gets tiring to have to go through pages and pages on a topic that really gets no where but are filled with no real world facts/info. Just another comment that would get answered another few pages down the road and that's maybe so. I'm still learning about this myself as I have a 2AZ-FE on a 2007 vehicle that may be consuming oil.


If a vehicle already has a leak, then there's no reason not to try an HM, the damage is already there and going to have to fix it anyway. But I would stick to regular non seal agent oil otherwise, until that time.

I don't see a uoa providing much information in this regard. If you want to run HM oil in a non leaking motor, I give a 50/50 shot of developing a leak. There's just no reason to F with the stuff, if you have a non leaking motor, that motor will run fine 150's or 200,000 miles on regular DINO oil, with no oil burn issues..


Most don't even keep their vehicles that long , IMO its all Bling factor mostly, in what people want. But yeah seal agents, seal conditioners , what ever your preference to call them, they will have a definite effect on the seals in swelling and softening, whether that's creates a leak or no leak, that's your gamble.
 
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