That stuff is big time thick @ 40c . Looks like Pennzoil 15w-40 diesel oil does at 40c . If the engine is saying ouch , give me something thinner in October , I assume it will be screamingas morning ambient drops during cold starts Or do you live on the Equator ?
I firmly beleive the Fe will continue to elevate but at an accelerated rate because of it .
Is it oxidative thickening or is it a just a straight weight formula ? Who knows , a baseline sample really needed to be sent in to see what the starting VI was and there's no doubt in my view that fuel mileage could be bettered .