It seems like 0W40 is a popular choice out there, as does 10W40. I'll be honest, I havn't seen it being sold at many places...perhaps since i've never kept an eye out for it. It doesn't seem like many people use 15W40...i'm starting to wonder why the dealer recommended it from day one.

With 0W40 and 10W40 what would you say is a good time for oil change intervals? With 15W40 I've always done 6-7000 km.