Yes, 3 years now. I know the Mobil 1 0w -40 is "recommended". Going to a 5w-40 with the high humidity & high temps in the south is no concern to me whatsoever. Call me cynical, but just because exxon/mobil has a financial arrangement with Mercedes Benz to "recommend" their oil, doesn't mean I'm using it. Personally, I don't do business with exxon, don't buy their gas, don't buy their oil. I did notice the new Pennzoil Ultra european formula oil is 5w-40 . I'd bet the house Pennzoil pays Ferrari to "recommend" Pennzoil Ultra as well. Just my 2cents worth sinced you asked.