Originally Posted by Mark963
I'll just throw in here that I find some of this confusing. At my local walmart, they just started carrying Castrol Edge Advanced 5W40 with the LL01 rating. Someone in another thread said it's been around a while. I don't think it's as good as the 0W40 European Formula, which is now much harder for me to find. It doesn't list a cold pour point and it's extremely thick at -35C. I might try Mobile 1 next time.
Other than being used as a tea leaf for deducing base stock composition, the pour point of an oil has little to do with quality. Only the listed approvals, specifications and licenses do that. You comment that the Castrol 5W-40 is "extremely thick at -35C" but the bottom line is that it passes the performance specification for a 5W winter rating. If your expected starting conditions require better cold cranking and pumpability performance than a 5W rated oil then you do need to find an oil with a 0W winter rating. There is no 5W rated oil that will match the extreme cold-weather starting performance of a 0W oil regardless of the base stock composition.
Nothing should be confusing about oils really. You pick one that has the required specification, license or approval your manufacturer requires and then you pick one that has a winter rating that is appropriate for your expected starting conditions. It's really not that difficult.
