Converting Diesel Engines to Run on Vegetable Oil


While Lloyd may well be correct that increased production of biodiesel by DIYers could lead to "a lot of exploding garages and gummed up dead diesels along the side of the road," another option available to drivers of diesel cars may prove less frightening: using straight or waste vegetable oil. Before explaining the process, we should note that the US Environmental Protection Agency has declared the use of vegetable oil for motor fuel a violation of the Clean Air Act, and violators could be subject to a fine of $2750. If you're willing to take that risk, though, as the New York Times' Jim Norman did, you'll discover that using vegetable oil to power your diesel engine could result in significant cost savings and a lighter environmental footprint.Besides that little matter of legality, running a diesel car on vegetable oil requires fuel system modifications that run about $2000 for parts and labor, and different driving practices: a driver must purge the fuel lines of vegetable oil during the last moments of a trip to avoid congealing, that purge function can only be run for 20 seconds or so before diesel fuel will run back into the vegetable oil tank and possibly cause an overflow, and s/he must keep an extra vegetable oil filter on hand, as it requires changing as soon as its served its useful life. Still, Norman speaks glowingly about the experience of driving his "veggie powered" Volkswagen Jetta:

...after more than 2,000 miles on veggie oil, there seem to be few disadvantages to the transformation. My car seems to get slightly better mileage, it seems to run a little more quietly and it has just as much zip as it does on diesel. According to test results I’ve seen, vegetable oil burns somewhat cleaner in most categories than diesel fuel, and emits absolutely no sulfur. What a veggie car does emit is a smell faintly redolent of the kind of oil being burned — or, in the case of used oil, the scent of whatever it might have cooked previously.

Vegetable oil, of course, is a renewable resource that emits no more carbon dioxide than next year’s crop will absorb and requires no drilling for soybeans in the Arctic National Wildlife Refuge or anywhere else. The environmentally aware will give you even more points in the game of green for using oil previously used for cooking.

Norman notes that it's unlikely that vegetable oil, whether new or used, will replace gasoline and traditional diesel: too many uncertainties still exist about the amounts of biofuel our agricultural sector can realistically produce, and what effect increased production will have on food prices. On a small scale, though, drivers like Norman can contribute to lessening our dependence on fossil fuels and moving towards energy sources that don't require quite the "devil's bargain" in terms of environmental impact. That last point motivates Norman and his wife Ginger to continue their experiment, which they've named the "Noah project." Noah is also the name of the couple's 11-month-old grandson, and both Normans hope their efforts contribute to cleaning and greening the world that he'll eventually inherit from them. ::New York Times via digg