So whats the gig with high mileage oils?

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665
Location
WA
I keep reading about these seal "conditioners" that slow or stop leaks. But what In getting out of that is it's some sort of seal sweller. Sure it may stop a leak, but wont it also increase the pressure against the mating surfaces of all the other seals in the engine, causing them to have some sort of premature failure too? Or am I totally off base here? I've also read a handful of posts stating something along the lines if "if you haven't used high mileage oil don't start"
 
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14,031
Location
Kendall, FL
Some will say you are correct. Other's will site that HM oils, especially ones meeting current specs, SN/GF-5, can be used in any vehicle. Valvoline has a video advising the use of their MaxLife causes NO issues and can be used from day one.
 
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1,007
Location
Oklahoma
There are all kinds of opinions on this. Some guy on here even decided to use it in a new car. In my view... I think HM oils are primarily intended for use on an older vehicle toward the end of its lifespan. There is no problem in using it when the time comes... I just wouldn't use it prematurely. Using it in a brand new car is certainly not ideal, and in my opinion, ridiculous.
 
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9,119
Location
Illinois
A friend has been using it in a vehicle since it was a year old with 3000 miles on it, as he wanted to a syntethic 10w-40. Now that vehicle has 76,000 miles... so I guess it isn't an issue anymore... smile
 
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519
Location
The Orca
I have gone back and forth, using high mileage oils, then not using them, using them again, etc etc for the better part of 150,000 miles driving on my 240sx and about 75,000 on my Sequoia and neither had sprung any new leaks or seapage in that time. As for the thought of high mileage oils causing enough swell to cause a newer, good condition seal to expand enough to cause undo wear, I have doubts that most of these oils have enough conditioner or sweller to do that. Granted I have no proof to back that up other than my own anecdotal useage.....
 
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24,703
Location
Dallas,Tx USA
I was wondering this same exact thing about Liqui Moly Motor Oil Saver. I'm thinking about giving it a go to help with my leaking valve cover gaskets (valve covers are literally buried,that's why I don't want to try to replace them,and I've been told not to even try it unless I'm experienced in replacing them on these engines,that the repair is not for an amateur ). Will the various other oil seals in the engine that are not leaking become "addicted" to the Motor Oil Saver and begin to weep or leak if you stop using it?
 
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22,648
Location
Apple Valley, California
i have used hm oil 2x and was pleased with the outcome.it completely stopped the rear main leak on my jeep in 1 oci.then i went back to regular oil. then my wides tahoe was burning a qt in 1200 miles. sthm allows it to go 5000m w\o having to add any oil. im sold.
 
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1,410
Location
Western Canada
High mileage oils are thicker, usually near the top of the allowable range for a given grade, which can slow consumption, sometimes. They also contain more seal conditioners than a regular oil does, because, yes, all oil contains seal conditioner / swellers... HM OIL has more... And, they MAY have more detergents etc... So, to summarize, HM OIL is thicker, and has slightly more additives of various types, costs $ 0.20 more per quart to make, marked up 5x + that retail... But it sure is creative MARKETING... how can I sell basically the same product for a higher price... ding! High Mileage oil... genius.
 
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8,307
Location
Grand Rapids, MI
Originally Posted By: geeman789
High mileage oils are thicker, usually near the top of the allowable range for a given grade, which can slow consumption, sometimes. They also contain more seal conditioners than a regular oil does, because, yes, all oil contains seal conditioner / swellers... HM OIL has more... And, they MAY have more detergents etc... So, to summarize, HM OIL is thicker, and has slightly more additives of various types, costs $ 0.20 more per quart to make, marked up 5x + that retail... But it sure is creative MARKETING... how can I sell basically the same product for a higher price... ding! High Mileage oil... genius.
How do you know that it costs 20 cents per quart more?
 

MolaKule

Staff member
Messages
21,947
Location
Iowegia - USA
Originally Posted By: SnowDrifter
I keep reading about these seal "conditioners" that slow or stop leaks. But what In getting out of that is it's some sort of seal sweller. Sure it may stop a leak, but wont it also increase the pressure against the mating surfaces of all the other seals in the engine, causing them to have some sort of premature failure too? Or am I totally off base here? I've also read a handful of posts stating something along the lines if "if you haven't used high mileage oil don't start"
What most people forget is that seal "conditioners" help with the pliability of seals. Seal "conditioners" are present in every commercially formulated oil. Seals may tend to stiffen under heat and chemicals present in the oil, so seal conditioner molecules diffuse into the elastomer and make the seal more flexible. In addition, the seal conditioners will increase seal swell, which means both the thickness AND the diameter of the seal will increase. However, increasing flexibility will actually reduce the force of the seal lip on a rotating shaft. In HM oils, they are a few tenths of a percent more. Also remember that seals are replaceable items that will eventually wear out. http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/530741/Seals#Post530741
 
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Messages
10,146
Location
Burlington, Ontario, Canada
Originally Posted By: geeman789
High mileage oils are thicker, usually near the top of the allowable range for a given grade, which can slow consumption, sometimes. They also contain more seal conditioners than a regular oil does, because, yes, all oil contains seal conditioner / swellers... HM OIL has more... And, they MAY have more detergents etc... So, to summarize, HM OIL is thicker, and has slightly more additives of various types, costs $ 0.20 more per quart to make, marked up 5x + that retail... But it sure is creative MARKETING... how can I sell basically the same product for a higher price... ding! High Mileage oil... genius.
I agree it's all marketing. Just because an engine has high mileage, if there are no issues it can use the recommended oil until the car is scrapped. Now if you do have an issue, then sure try a HM oil or address the particular issue with a product just for that issue as aquariuscsm has done with Liqui Moly Oil Saver.
 
Messages
484
Location
IL
Originally Posted By: geeman789
So, to summarize, HM OIL is thicker, and has slightly more additives of various types, costs $ 0.20 more per quart to make, marked up 5x + that retail... But it sure is creative MARKETING... how can I sell basically the same product for a higher price... ding! High Mileage oil... genius.
I buy M1 HM for the same price as regular M1.
 
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