Can biodiesel be used in any regular diesel vehicle, or must a vehicle be modified first?
Biodiesel can be used in any Diesel engine. That includes many trucks, generators, boats, trains, busses, and cars. The engine must be a DIESEL. Other than that requirement, you can just pour biodiesel straight into the fuel tank. No engine modications are necessary. Biodiesel even mixes with diesel fuel at any ratio so there is never a need to drain your fuel system.