Enjoying this discussion. Questions: for those using the Toyota oil, what is your cost at the dealership? It's a really good oil. I see that the oil filter is around $5, which is a good price.
To throw a monkey wrench into the discussion, I've started using the overseas manual to select my oil grade. [insert CAFE discussion here as to why only 0w-20 is recommended in the US; I don't want to clutter the thread]
For my model year, Toyota's 4Runner motor oil charts in Australia look like this:
The upshot of this is that I'm currently using 5w-30 for the winter, and may move to a 0w-40 or even a 10w-40 next summer. Don't know about using 15w-40, that's a bit thick for me but in high summer....
The engine doesn't have different parts if it's in the US, Australia, Asia or Europe. It's the same engine, same oiling system, same bearings, etc.
I got a great UOA using 5w-20 while towing last summer, but I'm testing the 5w-30 to see if it does better on the UOA. Including the 5w-20 UOA below for reference.
Currently using Amsoil, but likely changing to Schaeffer's once my stockpile is used up.
Flame suit on.