I would personally look for a decent 15w-50 or 10w-50 to give lower wear from cold start. There are big differences in the cold crank viscosities 10w,15w and 20w and therefore the rate of flow from cold.
As illustrated here
Grade................................0degC...............................100degC
10w-50...............................1034..................................18cst
15w-50...............................1535..................................18cst
20w-50...............................2300..................................18cst
These oils all have the same viscosity when hot (measured at 100degC) 18cst so no difference because they are all SAE50's, it's the cold start that makes the difference.
Hope this helps, see I might know a thing or two about oil!
Question
I'm curious about the green colour of the Porsche in your sig as my father had a (911s Targa?) in the early 70's which was that colour and I have never seen it since, it's a stunning green.......what is it called?
Cheers
Simon
