...today after exhausting all resources for some Mobil 1 Diesel oil. I've been a Mobil 1 Diehard for 20 years, but the stuff simply ain't out there, and the first oil change is way due. Oh well, better any Synthetic than none at all, I guess- :rant:

hey, royal purple is pretty good stuff, i run it in my 2500 burb, i saw the mileage actually go up a couple but i did change out the airfilter and it was old oil. It's expensive though

I had switched to Mobil 1 from Amsoil a couple years ago, but after all the marketing smoke and mirrors with the Truck & SUV crap, I went back to Amsoil. I have to order either one, and in the end I can get Amsoil cheaper.