When biodiesel was first being developed, the idea was to create a bio-based fuel that could run in stock, unmodified diesel engines.  While diesel engine manufacturers may have been consulted for technical advice, the push for biodiesel came from fuel developers, not engine people. 


Biodiesel fuel was to be compatible with petrodiesel, and of course blend with it: What we think of as biodiesel is typically a blend: B5, B20, etc. Biodiesel was to have the same qualities as petrodiesel such as be able to flow easily at cold temperatures.


Of course it had been known all along that diesels could run perfectly well on vegetable oils; the first diesels did this after all before petrodiesel was available. And nothing has changed today.


Small numbers of diesel owners run their cars or trucks successfully with waste, deep-fat fryer oil from restaurants and veggie oil from other sources. While they may encounter problems, such as a thickening of the oil in cold weather, those drivers just put up with problems and find their own solutions.


For now, engine manufacturers seem to have no interest in building engines that can run on used cooking oil. But there’s no reason other companies can’t build conversion devices that can make driving on vegetable oil a better experience.


V.O.Tech (Vegetable Oil Tech) has developed a conversion kit to eliminate the problem of slow-flowing vegetable oil in cold weather.  The system includes a filter, fuel tank heater, fuel heater, and insulated fuel lines. It uses both electric heat and engine heat to warm fuel before its sent into the fuel injection system.


V.O.Tech’s system also works with conventional, petrodiesel and presumably biodiesel.


Will diesel engine builders eventually offer their own fuel heaters to enable the use of vegetable oil as fuel? Unlikely for now. But biodiesel refiners now operating could actually benefit as would diesel drivers. One less production step, removing the glycerin (the greasy part of bio-based oils that makes it thicken in cold weather) would reduce the cost of their product. In essence, today’s biodiesel refiners would become vegetable oil refiners, not a bad thing at all if they could sell more fuel at a lower price.


Visit V.O.Tech’s website at