I would like to know, from anyone who knows alot about synthetic motor oil and other related additives, like fuel system cleaner, etc, how much fuel mileage can I gain by feeding my truck a "steady diet" of these products ?
Well synthetic oil will definately help in your quest for better mpg. Oil is the life blood of a healthy motor. I run synthetic and still change my oil every 3000 miles just for peace of mind. I usually run either royal purple or amsoil fuel system cleaner threw my hemi once a year and my mileage stays around 17-19mpg with mostly highway miles.
It is possible to find a slight increase in fuel economy by changing to synthetics, especially if the entire driveline is changed out. ie: engine, trans, T-case, and differentials. The new AMSOIL PI has shown an average mpg increase of 2.3% and up to just under 6%. Remember that all vehicles are going to show different improvements and of course higher mileage, less cared for vehicles more so. The PI is recommended every 4000 miles or 100 hours.
I think it's a waste of money to use any of these products on the chance of a gain in mileage. Peace of mind sure, mileage, no. Just run what came with it new and enjoy your truck and use whatever you save on not buying any of these things on gas.
i dont believe in using oil additives. i think its a scam. a good oil will do more then enough for your motor. i run mobil 1 synthetic, not for mileage gains but for the quiter and smoother idle it gives. your tranny fluid is already synthetic and i think the diff's are ass well but i dont remember. running a fuel injector cleaner or using seafoam every 5000 or so miles is about the only thing i would do. then again, some gas companies put fuel injector cleaner into it already so technically, thats not even needed.