Originally Posted By: ENGINEER60
10w-40 got a bad reputation for shearing due to the large amount of VI improvers it needed to cover the range.
Funny thing is that today, people use 0w-20s 5w-30s, 5w-40s, 5w-50s, 0w-30s, 0w-40s etc etc that have MUCH
more VI improvers than 10w-40 yet everbody seems ok with it due to slick marketing and misinformation
Actually it got a bad reputation for having poor VI improvers at the time that created excess deposits on piston ring lands. Today's VI improvers are nothing like they were at that time and are more stable today.
Do you have any technical proof that all those oils you list have "MUCH" more VI improvers than 10W-40? Makes for a nice dramatic post but I'd like to see facts to support it. What if I said instead that out of your list 10W-40 is the one that likely has the most?
I mean you are an ENGINEER, right? Engineers wouldn't say stuff they can't support, would they?