Originally Posted By: Quattro Pete
Thanks for digging these up. I'm still not sure I'm convinced of any wrong doing.
Originally Posted By: cchase
I'm admittedly terrible at searching this site for old UOA, but here is one at about 6k under the BMW OCI with a TBN at 2.0
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2136379
Modified engine/programming. Too bad he hasn't modified his OLM programming to account for this.
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Here's one at 15k that has thickened considerably:
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=218409&page=1
Wear seems appropriate for the OCI. The oil is spent, but it's hard to judge from the report whether it's past spent and actually hurting the engine.
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Here's a 15k OCI with a TBN of 0.1 and substantial thickening:
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1882963
It thickened up some, but I wouldn't call it substantial. The starting 100C viscosity is around 12 cSt for this oil. So this one thickened up about 13%. From a thick 30-weight, it became a thin 40-weight. Again, the oil appears to be spent, but I don't see elevated wear and the insolubles are low. Isn't the OLM doing what it was supposed to? Tell the owner to change the oil when the oil is done but before damage occurs?
I know we here on BITOG tend to freak out whenever we see a UOA that isn't picture perfect, but I think we're just too anal about these things sometimes. But I may be wrong... I don't follow my OLM either, which makes me just as bad I suppose.
I agree with you in principle. I'm not sure I'd want oil with those characteristics in an engine of mine though. I'm not sure how the "wear metals" correspond with sludge in the engine, either.
My original grudge is with the statement that BMW supposedly dislikes xw20 oils because preventing wear is somehow their utmost concern. If that was true, I suspect they wouldn't push 15k OCI's.