Looking to make a final decission on if i can go synthetic or not and even if i should... Please provide feedback. I have a 2003 F-350 6.0L Powerstoke dully w\ about 60K miles and a gas mod chip. I tow a 34' 5th wheel that weights about 12,000 lbs (2axle). This truck is mainly used for the camper and we go once a month regular as rain. I've been using 10w30 Rottella powerstroke oil in it since i got it w\ the recommended motrocraft filter. I need to get the oil changed in the next day or so and i want to get feedback. I can get the full oil change done with valvoline preimum BLUE 15w40 traditonal oil for about $93 or i can get Valvoline preimun BLUE extreme full synthetic oil 5w40 for about $125. What should i get? I'm unsure if my 2003 can use the synthetic oil or if it will damage anything, i love the truck and would HATE to hurt it in anyway(cant find any details in the manual). Also, if i can\do go synthetic should i still use the same FL-2016 motocraft filter or a diffrent one? The manual calls has a SAE viscosity grade table in it discussing expected temp ranges, 10w30 is preferred from -10 to 30 degrees and 15w40 from 30 to 100 degrees; where does 5w40 synthetic fall on this table. Sorry for all the questions trying to learn my best and i cant seem to find anyone locally that knows a hill of beans..
