When Rudolf Diesel built the high-compression engine, he intended it to use peanut oil as fuel. Because fossil fuel products were cheaper both to buy and run, the engine was converted to run on diesel fuel. Diesel engines can be run on petroleum diesel, bio diesel or vegetable oils. Waste vegetable oil, discarded when it is no longer food grade, can be refined and used as fuel in most modern diesel engines.
Alter your car so that it is equipped to run on waste vegetable oil. If you are mechanically inclined you can do this yourself, or you can pay your mechanic to do it for you. Alterations should include a second fuel tank, a method of switching between the tanks and a fuel heating system, which may be as simple as running the fuel line for the second tank through the radiator.
Contract with a local restaurant for its waste vegetable oil. Typically, you can get this for free because it saves the restaurant the cost of disposal.
Filter the oil into a clean 5-gallon bucket to remove any food particles. Use a filter that is at least 0.5 microns thick. Filters that fit over the top of the five gallon buckets the oil comes in can be purchased in the paint department of most home improvement stores.
Fill the second fuel tank in your car with the filtered vegetable oil. Fill your primary tank with standard diesel.
Run your engine on diesel fuel until the engine is warm and has had time to sufficiently warm the vegetable oil. The oil should be heated to about 158 degrees Fahrenheit before it is run through the engine, to ensure that it is thin enough to move through the valves with ease. When the engine has warmed, switch to the second tank.
Drive normally, switching back to the diesel engine about 10 minutes before parking your car. This ensures that diesel fuel, and not vegetable oil, sits in the engine while it is at rest. Allowing vegetable oil to remain in the engine of a parked vehicle could plug the injectors.
