High Mileage Oil Treatment

[mattpiotr]

i put some STP High Mileage Oil Treatment On My 86 350 and was wondering if this stuff was anygood?

[Dsquared]

i don't know bout the high milage,but i ran the regular STP oil treatment in my race car for years with no problems. as long as you keep the oil changed regularly,there shouldn't be a problem.that stuff is thick as molasses and don't break down as much as oil does.

[INSIDIOUS '86]

If it says it seals leaks don't use it. It will turn your seals to mush over time. The only help for a high mileage engine is a rebuild. While all these voodoo oils and sealants help restore performance for while they still are only temporary an the engine will go downhill soon after and quick. Just keep the regular maintanence and if you want help with the engine use hyper lube it's a gold bottle and works good for as long as your engine lasts
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[Number21]

Waste of money.

[Weasel Diesel]

STP oil treatment is a high level ZDDP product for high lubriticity ( ZDDP boost is also needed for flat tappet cams now that modern oils have cut back on ZDDP content ). The high milage version adds seal swellers to it to chemically soften seals that have hardened over time. Trying to bring "Rubber" or neopreme seals back to life isn't gonna happen. It breaks down the compound of the seal to make it softer. Does it work? Yes, for a while, a short while, then when the seal fails, it goes quickly, and aggressively. From the scientific tests posted at Bob the oil Guy's website, additives like ZDDP, and metal pore penetrating products like Zmax help out a bit fighting wear, however seal swellers will doom those seals.

I remember back in the 70's, the big "Fix" for leaking seals was to put brake fluid in the oil to swell the seals,.... stop leaking about 2 weeks then you would start seeing major seal failure.

[old Rusty C10]

the only thing ive ever used this stuff for is if i have a motor with a crank bearing going and i wanted to try to get some more out of it before a rebuild or replacement it will maks the noise for a while.. other than that its useless

[wilkin250r]

I'm wondering if the High Mileage oils are part of a conspiracy to get old engines off the road.

Like others have said, the additives that help "recondition" seals help for a temporary time, but they're damaging in the long run. You're basically rotting and deteriorating the seals. Yeah, they expand and soften, so they often seal better for a short time, until they fail completely.

[78 Big10 454]

I just use 50 weight motor oil.....

[Weasel Diesel]

Originally Posted by old Rusty C10

the only thing ive ever used this stuff for is if i have a motor with a crank bearing going and i wanted to try to get some more out of it before a rebuild or replacement it will maks the noise for a while.. other than that its useless

Gotta say, I'm with ya on that one.

[texassquarebodies]

Ive got 215k on my daily driver. I use the cheapest oil and a bottle of Bardahl No Smoke or add some Marvel Mystery Oil. It never did smoke. Seems like the motor is quieter with the No Smoke in it.

[tucsonjwt]

No. Bottom line - just thickens your oil. I ran straight 40W in my old 73 BB, but I think that might have hastened its cam failure (due to "soft lobes"?), which was common on early 454s.

[Lower]

Cam failure is accelerated by the lack of zddp as stated earlier.

[rayfinseats]

I would NEVER use STP. Red Line and Royal Purple have some good products. And if you want your vinyl upholstery to dry out and crack use Armorall.