Depends on how many miles is on the engine really. Me, Royal Purple, is what I choose, and some places believe or not, its cheaper and costs as much. Lucas engine additive thickens of the oil so there is less friction on initial start up. But, if it gets to hot, the additive will foam up. Ideally I would use a 0 weight in the winter and 10w during the summer, maybe 5w during spring and fall. That's a lot of oil changes though.