High Mileage Oil to Stop a Leak

Shel_B

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I took a look at the label on my M1 High Mileage oil today and noticed that it said that it's useful for preventing leaks. There was no mention of the oil stopping leaks. My experience is that it didn't stop a leak in my previous car. Based on the M1 label, I'd not hold out any great hope for the oil to stop a leak, although I'm sure there are some instances where that's happened. Just wanted to share that bit of info from the M1 label.
 
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It can keep seals from drying and can rehydrate seals that are dried. But if the seals are already healthy and hydrated it wont hurt them. It wont hurt to have a high mileage oil in a new engine. Many on here will tell you it caused no issues to do so.

If I'm not mistaken the api sp and gf6 specs want more seal additives than previous generations to combat against the thin little seals most cars have and the fuel dilution possibly interfering with seal life in the long term as well so it cant be bad.

Now as for stopping a leak it could if its a very small one but once its cracked open and leaking it wont do any good. if a seal is dried enough to where oil bypasses but isn't cracked it could help it in that case but those cases are rare.
 
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I would guess that language is related to liability. Pretty easy to tell if an oil has stopped a leak, impossible to tell if it's prevented one.
 
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It can keep seals from drying and can rehydrate seals that are dried. But if the seals are already healthy and hydrated it wont hurt them. It wont hurt to have a high mileage oil in a new engine. Many on here will tell you it caused no issues to do so.
Wait, seals "dry out" because they lose water? I thought the problem was cross-linking in the polymer chains causing it to become brittle and shrink?
 
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Wait, seals "dry out" because they lose water? I thought the problem was cross-linking in the polymer chains causing it to become brittle and shrink?
Yeah obviously because motor oil is petroleum based and nonpolar and doesn't contain water to hydrate anything and seal additives aren't water based either. Neither are engine gaskets compatible with water.

But when explaining it in layman's terms it essentially "dries out" such as living matter that's water based as an easy way to understand the function of a different thing that works in a similar way to what they know in day to day life.

People usually just want to know enough about something to understand it decently without getting into specifics unless they ask for it.
 
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I took a look at the label on my M1 High Mileage oil today and noticed that it said that it's useful for preventing leaks. There was no mention of the oil stopping leaks. My experience is that it didn't stop a leak in my previous car. Based on the M1 label, I'd not hold out any great hope for the oil to stop a leak, although I'm sure there are some instances where that's happened. Just wanted to share that bit of info from the M1 label.
High mileage oil definitely can work with reducing if not completely stopping leaks. I had a 1997 Mercury Grand Marquis that would burn/leak a quart of conventional 5w20 or 5w30 about every 2500-2700 miles, not bad but enough to annoy me. So one day when I was at meijer I decided to try valvoline maxlife Synthetic blend 5w30 because it was a fairly high mileage vehicle being it had around 204,000 miles. Made the switch and never burned or leaked another drop of oil doing 4500 mile oil changes until the car died of an electrical problem. Made me a believer and started my whole obsession with tribology a little over 3 years ago. Being I own all older high mileage I don't use anything but high mileage oil in my daily drivers and to this day have never had another oil leak or consumption issue. I would definitely give a high mileage oil a shot if you do drive a older vehicle.
 
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Yeah obviously because motor oil is petroleum based and nonpolar and doesn't contain water to hydrate anything and seal additives aren't water based either. Neither are engine gaskets compatible with water.

But when explaining it in layman's terms it essentially "dries out" such as living matter that's water based as an easy way to understand the function of a different thing that works in a similar way to what they know in day to day life.

People usually just want to know enough about something to understand it decently without getting into specifics unless they ask for it.
Dear Javier,
Then why does petroleum jelly help cure my chapped, dry lips?

Gracias
 
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I have seen a high mileage oil stop valve seal leaks. I knew someone who had a Rav4 first gen and it would literally look like her house was on fire when she started it. By some miracle I got her to switch to Castrol high mileage. At the time it was the easiest to find locally. Her father (old mechanic) always did her oil changes and ONLY used Havoline in all of their vehicles. I asked him why Havoline? He said "Because it is only 99 cents, what can be better than that?" So it was a challenge getting any other oil in there than he recommended.

Well, she used the HM oil and a few months later it did truly stop smoking completely. After that when she had an issue, she would ask me my thoughts on it lol.
 

Shel_B

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People usually just want to know enough about something to understand it decently without getting into specifics unless they ask for it.
How about explaining it in a more correct and precise way?
 
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HM oil significantly reduced oil consumption of my old Mazda 2.5 V6. However, it did nothing to stop or slow a timing cover gasket leak in my wife's Toyota. That gasket was so dry it cracked like pretzel sticks when I replaced it. I guess it depends on the gasket material and condition. It may work in some cases. Cheap to try, nothing to lose.
 
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HM oil has;

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Yeah obviously because motor oil is petroleum based and nonpolar and doesn't contain water to hydrate anything and seal additives aren't water based either. Neither are engine gaskets compatible with water.

But when explaining it in layman's terms it essentially "dries out" such as living matter that's water based as an easy way to understand the function of a different thing that works in a similar way to what they know in day to day life.
No that’s not at all what happens. And most engine gaskets are very much compatible with water.
 
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