I've been searching at all the local auto parts stores here in Melbourne Florida and can't find any 0-30w synthetic at all, and the Mobil 1 5-30w doesn't have the MB certification on it, but the Mobil 1, 5-40 w does. But while I have read on this forum, and in my manual as I seem to recall, that it is ok to use 5-30w, I have never read that it is ok to use 5-40w anywhere... Is there a reference document somewhere saying that 5-40w is ok to use? Having been changing oil for some 45 years, my gut call is that 5-40w would work just fine here in Florida, but I'd like to see it in writing. Till then, I'm going to continue annd try an find the MB certified 0-30w... Any suggestions from you guys? Best regards -- Bob