Mobil 1 has come out with a new synthetic oil designed for higher milage cars . . . its called super syn. I haven't used it yet but plan to use it in my aging Contour insted of the regular Mobil 1 I now use. As for the difference between full synthetic and "dino" oil. Your engine will run cleaner, cooler, last longer and get better gas mileage using synthetic oils. Using synthetic oil in conjunction with a good fuel injector cleaner like Red Line will keep combustion deposits down to a minimum and thus keep from fouling the EGR sytems that Ford seems to have so much problem with. When ports clog in Fords EGR system, the check engine light comes on and remind you that there isn't enough flow thru the EGR . . . clogging. However, if you trade cars often it doesn't really matter. I drive almost all of my cars past 200K so its worth it for me. If you change your own oil, it cost about the same as letting a garage change your oil using dino oil. Considering the increased gas mileage, it about evens out in the short run. I don't see much down side to using synthetic oil.
