Originally Posted by kbsilver
Depending on the year the car it's rated for a max of 5%-7% bio diesel content. Believe one of the main issues is lubricity. While Bio has great Cetane ratings, it has much lower lubricity. This can result in High Pressure Fuel Pump (HPFP) failures. Not sure if the very expensive injectors are impacted. I'm sure your warrenty would be voided if a fuel system failure occured while running 100% bio.
Lubricity of biodiesel is many times higher than petro diesel. The main issue is viscosity and and the fuel quality, ie ASTM standard fuel. As little as 2% biodiesel added to diesel replaces the lubrication lost by going from high sulfer fuel to low sulfur fuel.