I have a 2005 Fleetwood Pace Arrow - GM WORKHORSE would it be wise to put in full synthetic oil or semi-synthetic oil? The engine has about 45,000 miles on it.
Synthetic is far superior to Dino. Chances are you won't have engine problems with Dino provided you change the oil often enough. But, full synthetic is fairly cheap these days (about $24 for a 5-quart jug at Wally World) so why take a chance?