When to actually start using high milage oil.

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Is it a good idea to run an OCI or 2 of HM oil as preventive maintenance to keep seals from leaking?

also i have noticed M1's HM oils have an extra dash of ZDDP in them and are only SL rated. so maybe its more then just seal conditioners
 
Yes, Mobil's synthetic HM oils have a little bit "more" in a few different areas:
More anti-wear
More detergents
Higher viscosity
Seal swell agents
Higher flash point
 
Originally Posted By: Ken2
When to use "oil for high mileage engines?" When you have too much money in your pocket.
Around here, the HM oil is generally the same cost as the regular version or $2 more for a 5 quart jug at most. How is that deep pockets?
 
Originally Posted By: Donald

While they may have or not have conditioners, they have additives that cause seals to swell. I would not use a HM oil until I had a seal leak and had tried other things like Auto-Rx and synthetic oil (not together) to deal with a leaking seal.


I would assume the seals swell back to their original size after shrinking. If they were to
swell up larger than their original size, a lot of cars would be springing leaks out there.
 
There is no proof from anyone I can find on this site that HM oils swell the seals. I think someone has started an urban myth. The additive in M1 HM oils only conditions the seals in cars to keep them pliable.

When should you use a HM oil? When the rubber and seals gaskets around the engine become brittle? By then it may be too late... so 75K miles is a good chalk line. Each vehicle will be different based on the environment it has lived.
 
Originally Posted By: JasonBraswell
There is no proof from anyone I can find on this site that HM oils swell the seals. I think someone has started an urban myth. The additive in M1 HM oils only conditions the seals in cars to keep them pliable.


BRAVO!!!

I agree it should be used BEFORE problems develop... My '92 Grand Marquis had bad valve stem seals(a known issue in pre '96 4.6L) and I did try HM oil at around 110K mi with no detectable improvement... I also had a '93 with exact same engine and only 65K mi, by 80K mi it was begnning to use some oil due to the seals starting to fail... That one got HM oil 30K mi earlier and oil consumption never did get nearly as bad as the '92, even at 155K mi when it was sold...
 
Originally Posted By: JasonBraswell
There is no proof from anyone I can find on this site that HM oils swell the seals. I think someone has started an urban myth. The additive in M1 HM oils only conditions the seals in cars to keep them pliable.

When should you use a HM oil? When the rubber and seals gaskets around the engine become brittle? By then it may be too late... so 75K miles is a good chalk line. Each vehicle will be different based on the environment it has lived.



very well said! ^^^
thumbsup2.gif
 
I've currently got 337k on my Mazda - it gets HM oil if that was the most recent rebate deal - and then its usually a HM syn blend. Other OCIs are with whichever syn was recently rebated. Car hasn't complained at all.

80k miles is LOW for me and my family. Anything under 100k is like a 'new car'! 75k = High Milegae pffft.
 
Originally Posted By: JasonBraswell
There is no proof from anyone I can find on this site that HM oils swell the seals. I think someone has started an urban myth. The additive in M1 HM oils only conditions the seals in cars to keep them pliable.


While I cannot definitively say that HM oils actually use seal-swell agents, the additives do exist - although as stated it conditions the seals to keep them pliable.
-If you think about it like you would a hair conditioner, sometimes when you have dry, brittle hair you make it more healthy by using conditioner and in many cases save the hair from permanent damage. However sometimes your hair is dried and brittle beyond repair and all the conditioner in the world won't help. (If you don't have much hair or don't use conditioner than think about your wife/girlfriend's hair instead).

Seal-swell agents are additives which maintain the integrity of the seals. Typically these additives include polyesters, some phosphorus derivatives, and proprietary chemicals. Seal-swell agents are more commonly used in transmission and hydraulic fluids where seal compatibility is of much greater concern; although we are seeing it become more common place in engine oils - with most companies claiming to use them in HM oils.

Seals are not like those growing monsters that you get for the grandkids to put in water and watch get 100x bigger. They can only be as pliable and "swollen" as space and the chemical makeup of the seal itself allows.
 
My '07 Outback 2.5i just turned over 70,000 miles. It is seeping oil from the the head gaskets (no drips yet, just wet). This is a very common problem with Subarus, obviously a design defect.

After reading that many folks were still seeing HG leaks despite statements that Subaru solved the problem in 2003, I switched to M1 HM 5W-30 at 62K miles. The next OCI at 68K miles was also M1 HM 5W-30. It started seeping sometime in the last 2K miles.

So in my case, the HM oil didn't help. Or maybe it DID help, and the leak would have been worse if I did not switch to HM oil.

The real fix is multi-layer steel head gaskets, available aftermarket. Subaru should have used MLS at the factory.
 
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As a Subaru service manager said to me, when asked, "if a high mileage oil could stop external oil leaks on the Subaru headgasket problem you wouldn't like what it was doing to the rest of your engine."
 
But to continue my 2008 Subaru 2.5i N/A had an external oil leak, headgasket, driver's side rear that was fixed under warrantly at 52K miles. After using Castrol GTX 5W30 oil til then I switched to Valvoline DuraBlend 5W30 for a stouter oil (lot of high speed 3200RPM western states trips) that will last me til @ 77K (bought it on sale). My plans are to switch then to Valvoline MaxLife synthetic blend red bottle 5W30 as a higher detergency, seal conditioner oil to draw the "chalk line" for potential Subaru oil leaks around valve covers, front seals, etc.
 
I guess I don't understand something, not all that unusual... If you have a motor with HM on it, yes I know that is a relative statement, but say that you do. Wouldn't it be better to run a HM oil before you notice any issues with oil leaks/consumption?

It seems that being proactive and not having leak issues would be the better thing to do. Do the additives cause any issues with seals that are not leaking? I'm under the impression that these oils will help condition a motor, depending on what's included in them.

Cheers!
 
I think time is also a factor, regardless of mileage you could give your car a HM oil dosage by 10 years of service life. A couple oil changes with a HM oil(I do this for most used cars I buy since they are generally over 75k miles or 10 years lol) and start them off with 3 oil changes of any 1 HM oil I prefer. Then, swap them over to synthetic(or settling for conventional if warranted) as I get the other maintenance/service history caught up to snuff.
 
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Originally Posted By: JasonBraswell
I thought head gasket failures leak coolant... not oil.


Head gaskets can leak oil, coolant, combustion gasses or any combination of them. The leak may be internal, external or both. Depends on what part(s) of the gasket fails. Some engines are more prone to a certain type of leak, but that doesn't mean the gasket can't fail a different way.
 
Originally Posted By: JasonBraswell

When should you use a HM oil? When the rubber and seals gaskets around the engine become brittle? By then it may be too late... so 75K miles is a good chalk line.
Originally Posted By: TFB1

I agree it should be used BEFORE problems develop... My '92 Grand Marquis had bad valve stem seals(a known issue in pre '96 4.6L) and I did try HM oil at around 110K mi with no detectable improvement...


I see no reason to use HM oil unless a leak is present. Why is 75k to 100k the magic number to start preventative maintenance? In theory if you wanted to condition seals, shouldn't the additives by put in use much, much earlier? Say like starting with factory fill? I fail to see why two engines with 200k miles on them, one using for example PYB exclusively, the other w/ some sort of HM fill, one would be considered in better shape than the other.
 
Originally Posted By: ron917
My '07 Outback 2.5i just turned over 70,000 miles. It is seeping oil from the the head gaskets (no drips yet, just wet). This is a very common problem with Subarus, obviously a design defect.

After reading that many folks were still seeing HG leaks despite statements that Subaru solved the problem in 2003, I switched to M1 HM 5W-30 at 62K miles. The next OCI at 68K miles was also M1 HM 5W-30. It started seeping sometime in the last 2K miles.

So in my case, the HM oil didn't help. Or maybe it DID help, and the leak would have been worse if I did not switch to HM oil.

The real fix is multi-layer steel head gaskets, available aftermarket. Subaru should have used MLS at the factory.


What oil were you using before the switch to Mobil 1 HM and what OCI were you doing.

You may have just clogged up the filter if you didn't follow the correct switch process when changing oil brands etc.

Have a read of the link below:
http://www.pecuniary.com/faq/high-mileage.html
 
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