I'm new on this forum so, Hello everybody.
On the subject of "MFG approved" oil.
On of my brother is in charge of the "replacement parts department" in a quite big OPEL dealer (I live in europe).
A few years back (5 or 6 he remember) they began to have customers having trouble with some of their engines loosing power after a few thousand Km. Everything was running fine except that the power was gradualy disappearing more and more every day.
Guess what it was ? The camshaft was almost totally worn out due to friction with the tappets!!!!
Yes, an almost round camsaft!!
He reported the failures to OPEL as did the other OPEL dealers he knows of, who had the same problem (my guess is that it must have been in other country too).
OPEL investigated the problem and solved it by sending to the dealers.....a different oil!!!! The original "MFG approved" oil that my brother bought for the servicing in their garage was apparently not so appropriate.
My point is that manufacturers don't necessarily knows what's best for their cars. They don't test everything, in every way possible because it would cost them too much.
Of course, this is an extreme example but I think it illustrates well the point.
When discussing "MFG approved" oil and "OEM original parts", lets not forget that the main goal of nearly every industry is to MAKE MONEY RIGHT KNOW !
Of course, long-term reputation is still (hopefully) a small part of the equation but, thanks to the very pressing stock exchange market we live in, this is becoming less of a concern for them. And if you think that "big oil" isn't contaminated, well, welcome in wonderland.
We are responsible too for this state of affair (not all of us hopefully): people don't want to keep their car, TV, computer,phone, camera, etc...forever. They want the newest.
So, the industry responded kindly with products that last just long enough for their "expected live-span".
I'm not saying that there isn't any "good" products out there, but they are vanishing more and more every day.