How to Convert a Diesel Engine to Vegetable Oil

How to Convert a Diesel Engine to Vegetable Oil thumbnail
Straight vegetable oil can be used in a converted diesel engine.

So there you are, the wind blowing through your hair, your favorite tunes playing in the radio, a vast expanse of highway ahead of you; just you and the open road. And in your nose the pleasant smell of...french fries? Sounds strange of course, but that would be the case if your diesel car ran on vegetable oil. In fact, any diesel engine can be converted to run on either straight vegetable oil (SVO), or waste vegetable oil (WVO). Converting a diesel engine to run on vegetable oil is a creative way to cut down on your fossil fuel consumption.

Things You'll Need

  • A car with a diesel engine
  • Vegetable oil conversion kit
  • 4-to-5 plastic jugs
  • 4-to-5 100-200 micron filters
  • Large strainer
  • 2 large plastic barrels
  • Barrel pump with hose
Show More


    • 1

      Purchase a vegetable oil conversion kit for your diesel vehicle. Vegetable oil conversion kits are available for online purchase from companies such as Greasecar Vegetable Fuel Systems, Plantdrive Vegetable Oil Fuel Systems, and Frybrid Vegetable Oil Systems.

    • 2

      Install your vegetable oil conversion kit. You can do this yourself, or have it installed for you by a qualified mechanic. If you decide to install it yourself be sure to follow the manufacturer's instructions.

    • 3

      Install a second gas tank for vegetable oil. You will still need the original tank for diesel or biodiesel, especially if you live in a colder climate. Be sure to install a switch so that you can alternate easily from one fuel tank to the other. Vegetable oil thickens at lower temperatures so it is essential that you warm up your car before switching over to vegetable oil, and later switch back to regular fuel to flush out your fuel lines before turning off the car.

    • 4

      Locate a source of vegetable oil. You can run your diesel engine on straight vegetable oil from the supermarket, but that can quickly become expensive. Your best bet is to seek sources of waste vegetable oil. Restaurants are the best sources of waste vegetable oil as they empty their fryers frequently. Restaurant owners have to pay to have their waste oil taken away, so they are generally willing to give it away for free.

    • 5

      Insert the end of the barrel pump into the source of waste vegetable oil, and place the hose inside one of the empty plastic jugs. Pump or crank the handle of the barrel pump facilitate the collection process. Repeat this process until all of your jugs have been filled, or until you are satisfied with the amount of oil that you have collected.

    • 6

      Filter your collected waste vegetable oil. Before you put the vegetable oil in your diesel engine, you must make sure that all food particles are removed from the oil. Once you have collected your oil in plastic jugs, pour the oil through the large metal strainer into one of the large plastic barrels. Allow the oil to settle for several days. This way any extra food particles will sink down towards the bottom of the barrel. Using the barrel pump, pass the oil through the 100-200 micron filter and transfer the oil from the first large plastic barrel to the second.

    • 7

      Place the end of the barrel pump in your filtered vegetable oil, and place the hose end of the pump directly into your vegetable oil tank. Crank the barrel pump to transfer the oil to your tank. If it is too difficult to pump the oil directly into your vehicle, transfer the oil to a gas can and pour it into your gas tank.

    • 8

      Start your car using regular diesel or biodiesel. Once the car has warmed up, switch over to your vegetable oil tank. Be sure to switch back to your diesel or biodiesel fuel tank several minutes before your turn off the vehicle. This will ensure that the vegetable oil will not congeal in your fuel lines.

Tips & Warnings

  • Older diesel engine have rubber seals that must be replaced before converting your car to run on vegetable oil. If you do not replace them the oil will deteriorate them.

  • If you convert your car to run on vegetable oil, you are probably voiding the warranty on your vehicle.

  • Running a vehicle on vegetable oil is not approved by the Environmental Protection Agency and may be subject to fines.

Related Searches



  • Photo Credit corn oil image by dinostock from

You May Also Like

Related Ads