Originally Posted by Ndx
Originally Posted by benjy
oils with very wide spreads need more real synthetic in the base oils and they prolly burn off faster than a 10-40 using lesser base oils!! most users do NOT NEED OW OILS!
Agreed, but 0W is perfect for starts in -20C or colder...
And so is a 5w-30. Just because it's 0W, that does not mean that it is thinner or flows better in regular winter temperatures for most folks. The idea that 0w oils are universally better or thinner at cold temps than a 5w, just isn't true. Most 5w-30 resource conserving oils will offer just as good or better cold temp properties (typically thinner at cold start temperature, to a point) than a 0w-40 will. Now if you're in northern Alaska or something where absolute lowest pour point is a concern, then sure a 0w oil would be warranted.
Between the two choices, I'd pick Castrol 0w-40. Castrol, in my opinion, has always made excellent "euro-spec" oils, and usually have a broader product offering in that category. I have fond memories of randomly stopping at Autozones in search of the green 0w-30; have used lots of that stuff, and their 5w-40 / 0w-40 Euro oils with excellent results.