Originally Posted by michael.g
I switched to Mobil One Full Synthetic at the first oil change. Used Motorcraft Oil Filter.
Our 2009 Greyhawk (on a late 2008 built E450) required 6 Quarts of 5W20.
Don't want to start an oil war either, the newer V10 Ford recommends 5w30. I think the 5w20 is not robust enough for carrying a house down the road.
They originally recommended 5w20 for better fuel mileage, but it didn't help much at all. I also recommend the Mobil 1 oil filter. Its better suited for Mobil 1 oil and better built than the Ford filter. JMHO