Converting Diesel Vehicles to Run on Waste Vegetable Oil, by Polar Bear

When Rudolph Diesel invented his internal combustion engine, he used refined peanut oil as fuel. The reasoning behind it was that farmers could essentially grow their own fuel for their tractors. Diesel cars have been widely manufactured and used all over Europe, but never really caught on in the United States. Diesel pickup trucks and Big Rigs are common in the US, and are renowned for their torque and towing abilities. These rigs run on “Dinodiesel”-typical diesel fuel refined from petroleum. You may have heard of the term “Biodiesel.” Biodiesel is a type of diesel fuel made by taking vegetable oil and adding Lye and Methanol to remove the glycerines and convert the “esters” in to “methyl-esters.” Dinodiesel has a lower gel point in cold weather than biodiesel. Fuel stations around the country have only recently began carrying biodiesel. Enough history and chemistry, this article is going to give you the basics of converting a standard pickup truck or car so it will run on Dinodiesel, Biodiesel, or Straight Vegetable Oil! As a motor fuel in a survival situation, or for daily use, Waste Vegetable Oil (WVO) or Straight Vegetable Oil (SVO) is hard to beat. It can be stored for years if a biocide stabilizer [such as Pri-D] is used, there is a potential fuel cache behind almost any restaurant, and while other folks are waiting in gas lines, you could easily check out at Costco and have them load a pallet of soybean oil in your truck!
Note: Most all diesel cars and trucks will run biodiesel without any conversion at all, but you must understand that biodiesel is a very powerful organic solvent. It will clean out old deposits and varnishes left in your fuel system by years of dinodiesel use, and may clog up your fuel filters shortly after you start using it (it is a good idea to carry spares!) Biodiesel also attacks natural rubber and breaks it down, so on cars and trucks older than about 1994, the fuel lines need to be replaced with synthetic lines, such as Viton® or Gates® 4800 marine grade series hoses. Now, without further adieu, let’s talk about conversions!
For the purposes of this article I will describe the conversion of a 1983 Ford F-250 extended cab with a non-turbo 6.9 liter diesel engine (my first conversion!) This particular truck has dual tanks (very important, but not 100% necessary.) I designated the mid ship fuel tank for the veggie oil tank for two reasons: 1- the veggie oil must be heated and we don’t want to lose heat in the long travel from tank to engine, and 2- the hose we need to run (Triple bypass hose or “3B” available from Golden Fuel Systems.) is expensive! Basically, we need to install a heating device in the front tank to thin the oil, add an additional filter with heated housing to run the veggie through, and splice in all of the lines. All of the fittings required (hose barbs clamps, etc) can be purchased at Home Depot or some other hardware store. A kit with complete instructions and all parts can be purchased from Golden Fuel Systems,,, Lovecraft Biofuels, or others, but I have found that the parts can be purchased individually for much less.
First, we need to purchase a transmission oil cooler. It doesn’t have to be enormous, 5”x10” will do, just remember that we will be cutting a hole in the fuel tank to put it in, and we do not want to interfere with the function of the fuel gauge float or the pickup. Now we drop the front fuel tank, and keeping in mind what we said about the float and pickup, cut a hole in the top of the tank the same size or just a bit bigger than the end of the transmission cooler. They are usually around an inch and a half thick, so you could cut a 1-1/2”x5” hole. I drilled a 1/2” hole and cut the rest out using a $7 pair of sheet metal nibblers from Harbor Freight Tools. Now that we have created a hole in the top of the fuel tank, a patch plate will need to be fabricated. I used aluminum, less than an eighth of an inch thick, and 1/2” bigger all around than the hole we cut in the tank, so for us it would be 2-/12”x6”. The plate needs to be fitted with hose barbs so the transmission cooler can be attached to it (one set of hose barbs sticking in the tank) and one set sticking out so the 3B hose can be attached to the other side. For clearance issues, I put those on a 90 degree elbow. The 3B hose is essentially 3 hoses bundled together, one 3/8” fuel line and two 1/2” coolant lines. Attach the transmission cooler to the hose barbs on the patch plate and insert the tranny cooler in to the tank, positioning it so it does not hit the fuel pickup or the gauge float. Then apply some high temperature RTV silicone sealant where the patch plate meets the steel of the tank and use self-tapping sheet metal screws to secure it in place. The metal shavings caused by the self-tapping screws can be removed from the interior of the tank with a magnet and a string. Now we must set aside the tank and mount the heated filter housing and filter.
There are many heated filter housings on the market today. Vormax®, Hotshot®, and Hothead® are just a few. Essentially, the heated housing is a machined block of aluminum with water jackets bored through it to allow for hot engine coolant to pass through. The filter merely screws on. Keeping the veggie oil hot is a key component to the system. Hot = thin and cold = thick sludge! The filter should be a Racor® filter with a water separator. This filter housing and filter should be mounted anywhere close to the tank, but it must be between the tank and the tank switching valve; otherwise it would take much longer to re-prime the system with dinodiesel fuel. Why do we have to switch? Because veggie oil is much more viscous than diesel fuel. That is why we heat it.

Essentially, the process of running your truck on Veggie Oil is this:
1. Start your truck on Dinodiesel (with the fuel tank selector switch set on the rear tank.)
2. Drive the truck. When the temperature reaches about 170 degrees, flip the switch to the front veggie tank.
3. It shouldn’t take more than a few minutes for the veggie to replace the diesel in the fuel lines and filter. You will notice a slight drop in power and your engine will quiet down and run smoother.
4. Voila! You are now running on veggie! (Note: this may not be legal in some states! If you are getting your Veggie for free as waste from a restaurant then you are not paying fuel and road taxes on it! This upsets the Government for some reason, so be careful!)
5. Remember, you must flip the fuel tank selector switch back to the tank containing dinodiesel and allow the engine time to re-prime with that fuel before shutting it down. Depending on the outside air temp and how long you are going to let it sit before restarting, I have left mine for up to an hour. Veggie diesel that sits and cools in your injector pump and filters may “kill” your vehicle. It will be very hard to start!

Once the filter housing and filter are mounted and the 3B hoses run from the tank to the heated filter housing and then to the tank switch, the rest of the hose will replace the existing fuel line from the tank switch all the way up to the low pressure lift pump mounted on the engine. Just unplug the old fuel line and plug in the new one. Then take the two coolant lines and splice them, one each, in to the heater core lines running out of the firewall. Make sure you add coolant to the engine once it heats up so the new coolant lines you have installed can be fully primed. The last thing we need to do s install a heater band around the existing fuel filter. The fuel filter is the last area that we need to heat. A 12 VDC band heater that will heat up to about 160 degrees is plenty. Once again, available from Golden Fuel Systems. The front tank may now be used for veggie oil, biodiesel, or DinoDiesel, in any combinations or mixtures!

A Word on Harvesting Veggie Oil:
New, fresh oil is obviously the best. It does not need to be filtered or treated for storage. There is also no worry of having water contamination. Much less expensive (free actually, with permission from the restaurateur) is Waste Oil. This oil can be harvested in a number of ways. I use a 2” trash pump and store the oil in 55 gallon drums or 275 gallon tote [palletized] tanks. Do not use “creamy” or hydrogenated oils! Trans fats in hydrogenated or creamy shortenings are bad for your body and your engine! Only use transparent oil. It is best to pump it in to drums and let all of the little bits of food settle out, and then siphon off the top layer of oil for filtering. Your filters will last twice as long this way. I use a $25 one inch pump from Harbor Freight to push the oil through a 10 micron filter bag in a X-1 housing. These are available through
In a G.O.O.D. situation it will probably be too much to pack all of your harvesting and filtration stuff with you, so I recommend Golden fuel system’s ONESHOT filtration unit. It is small, runs on 12v and is totally self contained.
This article is meant to be a primer only. I strongly recommend purchasing some books on conversions and doing your research! (This is my obligatory disclaimer, I am not responsible for your success or failure, or mechanical ability.) The book “Sliding Home” by Ray Holan and “From the Fryer to the Fuel Tank” by Joshua Tickell are both awesome references. Well, I hope you are hooked and are going to give veggie oil a try. The two tank system takes a little getting used to, but you will smile every time you drive by a fuel station. It takes me only about one minute to siphon and filter 3 gallons of veggie oil. At today’s prices $3.15/gal in Portland, Oregon, I save around $9.45/minute or $567 an hour! If the two tank system is too much, Elsbett in Germany makes single tank conversion kits for Volkswagen Diesels (expensive-the kit for a 2002 Jetta was around EU1,200 Euros) and Lovecraft Biofuels makes a single tank conversion for Mercedes Benz Diesels for around $400.
Good luck in your conversions! Don’t be surprised if you start feeling the urge to stop at a fast food joint while running veggie oil- your exhaust will smell like French fries!

JWR Adds: For those of you that are not do-it-yourself tinkerers, I just heard that Ready Made Resources (one of SurvivalBlog’s first advertisers) now sells a home biodiesel making machine that can produce up to 330 gallons of biodiesel per day, at a cost of just 67 cents per gallon. This fuel can be used is standard (unmodified) diesel cars, trucks, and tractors, without the need to rig a separate fuel tank. Call Bob at Ready Made Resources 1(800) 627-3809 for details.