For those of you who are interested, I have contacted Cummins and researched their FAQ pages for their official responses concerning use of Bio-diesel and other alternative fuels in our ISB's. I will summarize here, but full responses are on their FAQ pages. There are three types they speak about: E-Diesel, PuriNox, and Bio-diesel. E-Diesel is diesel #2 with ethanol blended in, increases risk of fire and explosion, and indicates reduced life of fuel system components due to lack of lubricity. PuriNox is diesel #2 with water and an emulsifying agent to hold the water in suspension, and increases wear on the fuel pumps, gets fewer miles per gallon, and due to the water can cause corrosion in the fuel system. Bio-Diesel has improved lubricity for the fuel system components, but also has acidic animal fat base that can erode the seals and gaskets of the fuel system sooner. Bosch has stated that use of the E-Diesel voids the fuel system warranty, and has not indicated that for the other two as yet.