To pick up on Bottger's comment (and pick
on Bill some
), I'd add that while I agree with much of what Bill posted, I do disagree with some of it.
First, which "synthetics" are we talking about. Perhaps I shouldn't lay this one at Bill's feet, as the OP framed the discussion in these terms. As we've all seen from the never-ending "what oila are (are not) really synthetic" debates, there is an extraordinarily broad variety of different products that have now been made to fit under the "synthetic" umbrella. Heck, even some assumed-to-be-dino products contain a bunch of "synthetic" oil in them. For example, Mobil Clean 5000 (which Mobil does not push as a blend) contains enough syn ester that Frank Miller recommends against using it in the ARX rinse phase. Anyway, I'm not really convinced by conclusions slapped broad-brush against wide categories like "synthetic". Bill mentioned lower wear with M1 vs. the others noted -- what about Redline, Syntec (US or German), the many flavors of Amsoil, and so on? Are we generalizing about them all?
Second, as to the UOA, no, of course they don't "lie", but at least in their $25-50 form, they don't exactly tell the whole story either.
Third, as Bill recognizes by implication, most forms of what we call "synthetic" oil do last longer in service than "dino" oils generally do. For someone who stacks up the miles as heavily as I do (I fluctuate between 30-40k miles per year), reasonable extension of OCIs saves me
time in a way that's much more pertinent and important than saving a few bucks by using cheap oil and changing on short OCIs. Cost
may always be a factor, but this begs the question: how much of a factor? I have a whopping four quart crankcase -- for me, it's a very, very small factor. Of course, if you've got a vehicle with a really big crankcase, the math changes, perhaps enough to change the ultimate syn/dino decision for some users.
As far as MPG, this is really a straw man point. I've never looked to synthetics to provide mpg gains, substantial or otherwise, though I do see the theoretical arguments why they might have an advantage.
I'm waiting with baited breath for someone to do some back-to-back testing of conventional 0w-30 oils vs synthetic 0w-30 oils -- oh wait, that's right, conventional base oils aren't good enough to make a stable, customer-useable 0w-30. . .
