I wouldn't argue with much of those quotes, Cory. I never said it shrinks or swells seals that they seem to imply is what all the myths are about. Notice they *never* once mentioned detergent properties. Hmm - why is that? Is it possible that they are using strawman "myths" as a diversion? None of what they mention to counter the myths is what I warn about. We've had the discussion on that before, and I don't want to have it again (that's just a statement of fact - no emotion involved - we're speaking as friends).
Keep in mind when quoting companies defending use of their products that you can find statements by "reputable" manufacturers insisting that their product is an acceptable substitute for specific products (I'm thinking particularly of tranny fliuds and antifreezes here).
My beliefs on the subject are based on personal experience in the fairly recent past (with Mobil 1). People will choose who they want to believe, and I have no doubts that *many* people have made the switchover at high mileage with no problems. I equate that to deciding that you can run red lights without consequence because someone you know ran two red lights and did not have an accident or get a ticket. Not a perfect analogy, but just using it to support my point.
I will say that *IF* you know that you don't have more than light sludge in the engine, you're probably safe to do the change, but if that and the history of the engine, such as oil and filter change intervals, is an unknown, I would definitely say don't do it. If you have, not even small leaks, but just minor seepages, I would say definitely don't do it.
Not that this is relevant today - just some history - but when Mobil 1 first came out, they had a huge problem with getting their additive package right as far as seal shrink/swell. I jumped on the bandwagon when they first came out and immediately ended up with an engine with some oil leaks - wasn't fatal, but their product earned a big black eye during those days and, after tweaking it and getting it right, it took them years to overcome the bad publicity - I see they're still trying to counteract that "myth" (it wasn't a myth back then but would be today).

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'98 Concorde LXi - Candy Apple Red | Black chrome ring gages | Black Diamond headlights | Clear turns
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