As to the thin-then-thick mechanism, what happens, IIRC, is that early in the OCI, the oil can shear down some and therefore become thinner. Later in the OCI, as oxidation becomes more of a factor, it thickens. I'd defer to Terry on this and certainly would not try to pick this pattern from a UOA myself. None of my vehicles have themselves done this.quote:
Originally posted by fuel tanker man:
Hey...One of you guys need to show me the consecutive Redline UOAs where the wear trends down. So far, not a soul has come up with such evidence. It's likely a myth--but I'll reverse my opinion if someone shows the UOAs.
We do have some consecutive Redline UOA's here--but not one of them shows a downward trend in wear metals.
The Havoline UOA I mentioned earlier shows wear metals at half or less the Universal Averages with the exception of the Lead. But with Lead UA's at 9 ppm at around 6000 miles, the 22 ppm lead at 13K isn't out of line with the averages.
As for the oil thinning then re-thickening--being a layman I don't know how that can be determined. Perhaps one of you can tell us how we can know that...
Nonetheless, the oil did a fantastic job of protecting the engine.
Dan
I'm not sure that with that lead level you can say, without some qualification, that the oil did a great job.
I also agree with the poster above who pointed out that you need to reduce the raw wear numbers to "per thousand miles" to compare them on a fair basis. I pushed this idea with one of my earlier UOA posts, but for the most part, it has not caught on. I'd be more impressed with a syn showing a 10 ppm lead after 15k miles than I would be with a dino showing 5 at 3k miles.
Dang, I can't find anything else to disagree with you about...