Join Date: Jul 2007
Location: South Yorkshire
Common Rail diesel cars, such as the C-Max are incredibly complex, and cost thousands to fix if misfueled. It's a false economy to use 100% biodiesel in a common rail engine, as it WILL cause the fuel pump to fail and damage the fuel system. Ford recommend only a 5% biodiesel blend, and then only blends which conform to official standards. If you use a stronger blend you will invalidate your warranty, if you have one.
Older non-common-rail diesel cars can take 100% biodiesel because their fuel systems are simpler, and made to much lower tolerances.