Originally Posted By: OVERKILL
Not necessarily. M1 EP and AP 0w-20, which you and I recently discussed, just has more PAO on it versus a 5w-20, which can be made with Group III for example
Now of course that's likely not applicable here, but figured I'd mention it, as that's sometimes the case.
I see what you're saying.
For example, if you made a full syn 5w20 using entirely GroupIII, as I think Kendall has, you could "convert" that 5w20 product in to a 0w20 by substituting some PAO in for some percentage of the GroupIII, knowing that PAO would allow the cold cranking 0w maximum to be met. (PAO makes seals shrink, so alterations in seal swell chemicals may have to be made, and then you might need some esters for additive solubility... a can o' worms....http://www.machinerylubrication.com/Read/28601/switch-to-synthetic ).
If staying with all-GroupIII for your 0w20, which is what I assume Kendall did here, you would have to use thinner oils and boost the hot kv100 upward via more VII added.
Also, they might have over-shot the minimum new-oil kv100 knowing there probably would be VII permanent shear happening. Good idea to do that.
So that kv100 might (likely will) shear down at mid- to later life of the oil in the sump, but your cold 0w cranking should still be OK since VII mostly affects the hot temperatures, not extreme cold cranking.