I have run mostly 100% homebrew biodiesel in my 91 300d for about a year now and no problems.I did take the tank out and clean it before i started using it and i did change the rubber fuel lines to the bio-resistant stuff that Autozone has,i did not change the o rings on the delivery valves as i had recently done them.I did change the little return fuel lines too.I bought the viton stuff from Jim Davis at jim @frierpower.com. Might be that the softer combustion from the biodiesel would be easier on you "rodbender engine".I have about 5000 miles on bio now and have not had to change ANY fuel filter yet.
Hope it works as well for you as it has for me. Don
