I noticed that in Oxford a small outlet has started selling 100% biodiesel that apparently conforms to the new German standard. (I forget the number). To my mind bio-fuels are a no-brainer:- -almost no carbon dioxide emmissions -no dependency on foreign oil -provides agriculture a much needed boost -technology is here now While Volkswagen have very usefully stated all their cars with diesel engines sold since 2002 (including all brands, Audi, Skoda etc.) will run on the German standard for 100% blend, Mercedes have been rather more difficult. When I got my car serviced (C220 CDI) I enquired about running on biodiesel. Apparently no one had ever asked. Are people really this indifferent about environmental issues? Anyway they got back to me later with an e-mail saying Mercedes do not recommend running on biodiesel unless the car was specifically ordered to do so when being built. This seems like something of a cop out. My car is over three years old so I have no warranty to loose. But from my understanding biodiesel can be corrosive to rubber seals. This means if the car has any such seals in the fuel system, after enough time running on biodiesel they will fail, possibly causing a fuel leak. Not something even worth contemplating in my opinion, even though it may well be the case that there are, in fact, no seals in the C220 CDI (2002) that are prone to corrosion from biofuels. Anyone any information on this? The Mercedes dealer was frankly useless on this, and referred me to the general statement from head office. Anyway I had heard of conversions to change all the seals in the fuel system to ones that aren't corroded by biofuels. I hear this may cost around £600 which seems fine, but again the official Mercedes dealership I was at seemed to know nothing of the procedure. Does anyone know who carries out such conversions? I find it remarkable that I could now run my car on almost completely renewable resources with hardly any sacrifice on my part, yet I am held back by the ignorance of Mercedes-Benz!