There’s something to this, I think, meep… if you look at the 0/5W oils, as VI increases, so does Noack. We’re told high VI is very desirable, but when we look at the 10/15Ws we generally see much “worse” VI, yet UOAs show they are more shear stable, with very low Noack (some 5% or less!).
Also, when we look at many of the engines with heavy varnish, sludge, or phaser/timing chain issues- we see the OEM oil specs usually steer the user toward higher VI oils, especially when cold weather is involved.
Question: is the CAFE push and the “improved” formulation with high VI additives really just a planned self-destruction/continued service requirement? Like, with all these things lining up, intake valve cleanings & timing chain & phaser failures that seem to be improved by an “inferior” VI oil due to lower shear & Noack, can’t we seriously ask that question of oil blending experts?
I know no oil will stop engineering, machining, or materials defects, but all the signs make me wonder: if you ran an engine that called for a 0/5W30 instead on a 10W30 or even 15W30 (if it existed, of course) for a half-million miles, would there be statistically measurable wear and failure rate differences by sacrificing a few tenths of MPG while the engine was cold? I need an adult beverage now! 🤣