I know this isnt a forum for discussing biodiesel, but 'cause you asked...the methyl alchol used to make biodiesel, will cause most materials used for seals, tubing etc. EXCEPT Viton, to swell, crack, dissolve and eventually fail. If the diesel engine is kruddy from burning petrolium diesel, biodiesel could act as a solvent and loosen all the krud and cause issues... filters plugged, injectors gummed up... and without the krud there could be lubrication problems. Same thing when we switched to unleaded gas.
Thanks for all the input, my farm co op sells Biodiesel, I think B5 (5%) and I wanted to support them.. oh yea and it's cheaper. Nuf bout that.