Would You Use Veggie Oil to Fuel Your Vehicle?

Image Gallery Marcos Markoulatos and Ty Martin, of Lawrence, Kan., both run their trucks on filtered waste vegetable oil. JON HARDESTY

This may sound strange, but you can run your diesel car or truck on vegetable oil and nearly eliminate your use of traditional gas or diesel. For certain people, veggie oil could lead to major savings. Called veggie cars or grease cars, these vehicles have fuel systems modified to burn both diesel fuel and straight vegetable oil. The idea is actually a modern twist on the original intention for the diesel engine.

But even proponents say veggie oil is not for everyone because of the extra work it requires. Nevertheless, there is a small, but growing, part of the population that’s passionate about using grease to make their cars go. These people are drawn to this alternative fuel because it saves them money, gives them more control of their transportation fuel needs and makes a difference for the environment.

All this may sound too good to be true, and in some ways it is. Is it the most environmentally friendly alternative fuel? Should new vegetable oil or used grease be used? And here’s the real kicker: It’s technically illegal (see “Veggie Oil Vehicles and the Law,” below). So, before you start hoarding Wesson Oil, there are a few things you should consider.

Want Fries with That?

To get a sense of how this works, consider the example of Ty Martin. On Thursdays and Sundays the Lawrence, Kan., auto mechanic parks behind his favorite restaurant and heads inside for a hamburger and fries. As he eats with friends at the bar, kitchen staff fill a tank in the back of his truck with grease that was used to cook food just the day before. An hour later, truck and driver head home, both smelling faintly of burnt peanut oil. The used grease then propels Martin’s pickup all over town, all for free (except the food).

For Martin, burning vegetable oil means more than maintaining a dual fuel system. It’s a lifestyle, attracting the bohemian in a growing number of Americans who, for environmental, financial and/or political reasons, bristle over using fossil fuels for transportation. Whatever your motivation might be, if you have a diesel engine, it could run on cooking oil.

In fact, in the 1890s German inventor Rudolf Diesel originally designed his engine to run on vegetable oil.

A New Kind of Kit Car

The big challenge with using vegetable oil in Diesel’s engine was, and is, cold weather. Vegetable oil works best when it is hot — ideally 160 degrees — and it thickens like butter when it is cold. That means the engine has to be warmed up before it can run on vegetable oil, and the veggie oil must be flushed out before the engine cools down. Otherwise, you will have clogged fuel lines when you next try to start the car. To convert a diesel engine to run on veggie oil, you have several options.