Difficulty: Moderately Easy
Step1
Compare biodiesel to Straight Vegetable Oil. Using biodiesel is easier, since you can use it in a regular diesel engine and you can buy it at some gas stations. However, biodiesel is still made primarily of regular diesel. It is not as "green" or cheap as SVO. SVO is less expensive and completely natural. To use it, the diesel engine must be modified.
Step2
Decide whether you want to modify plant oil to run in a regular diesel engine or alter your diesel engine to use unmodified vegetable oil. With the first option, you can use commercially available biodiesel in a regular diesel engine. With the second, you could collect vegetable oil from restaurants, process it and use it in a modified engine.
Step3
Find out if there are any sources of biodiesel or SVO in your area. Ask your local gas stations if they have biodiesel or check Mapquest's fuel map. Review instructions for making SVO to run in your engine to see if you have the time and space to do it. Ask local restaurants if they will allow you to take used cooking oil.
Step4
Buy a diesel vehicle that can run on biofuel or be converted. Older vehicles are not recommended, since they contain rubber seals in the fuel system. Vegetable oil can cause the seals to wear out. Make sure the vehicle is not so rare that you can't find parts for it. Inspect it and test drive before buying.
Step5
Purchase a conversion kit if you decide you want to use straight vegetable oil. The kits include an extra tank and fuel line. The existing diesel tank is used to start the car, and the biofuel system kicks in once the tank is heated.
Step6
Follow the manufacturer's directions to install the kit or find a mechanic who can do it. Most kit suppliers can provide a list of mechanics in your area who will install the kit.