Are 0w-40 and 5w-40 the same thickness when cold??. I read a post on this site that said they had exactly the same thickness at the winter rating and the only difference was that 0w-40 had a lower pour point.
Could someone please clarify this for me.
The answer is no. 40C is not cold and hence is not an accurate measure of 'cold' thickness.
A 0 weight will be thinner at extreme cold because it has a lower standard cold test to qualify for. This is -35C.