Damn, and I was going to ask if you were drunk again
I always thought the W was for Winter... Guess that's not too far off
edit: regarding the single grade, it's just that grade all the time regardless of temp. Multigrade "starts" at the low # viscosity and raises commensurate with temperature until operating temp where it stays at the second # viscosity. I guess before multigrade oils in the "good ol days" the dudes would have to change motor oil grade with the season? :lol:
I wasn't really clear on those #s until recently too, read through this wiki page it has some info:
http://en.wikipedia.org/wiki/Motor_oil
