I bought a 98 Dakota 5.2 with 66K on it and want to start running synthetic oil it. I dont see any oil leaks at this point and dont want any new ones. As soon as I bought the truck I changed the oil which still had between 2k and 2.5k on it according to the little windshield sticker, but had probably been in there for 6 months or longer. (The previous owners husband died and she wasnt driving it) I changed the oil again 2K mile later with Mobil dino 5-30 and am running it 2K miles which brings me up to 70K miles. The oil, with exception of the oil that was in it when I bought it, doesnt look that dirty. I am thinking 5K intervals with either Mobil 1 10-30 or maybe if I can find the new Mobil 1 5-40. Filters as always will be Napa Gold. Does anyone see any problems with this senario?