Following this thread, always find the oil threads fascinating, some use pop corn to indicate ho hum. I'm a Rotella full synthetic fan, however blend would probably work as well, but what's a buck or two between oils? I prefer the 10/40 full synthetic but Rotella just doesn't sell it, at least not that I can find, 5/40 is it, probably doesn't matter a bit, the book just says, 10/40 blend I think. OK, pop corn folks, all done.