No. 5w40 synthetic is the equivalent of 5w40 conventional.Is 5w40 synthetic the equivalent of 15w40 conventional?
There is no 15W40 synthetic. 5W40 synthetic would be a bit thinner than 15W40 in hot weather, but since synthetic runs cooler, it would be a wash. I have been considering such a switch myself.
On mobil one website they say to use 5w40 synthetic in place of conventional 1 5w40. Even at Napa I was told the same. I don't see 1 5w40 synthetic on shelves. I just wanted make sure I'm doing the right thing.