Run a Diesel on Waste Vegetable Oil (WVO)

This story is part of Treehugger's news archive. Learn more about our news archiving process or read our latest news.
Active oil splash in white background
Yaorusheng / Getty Images

So, you’re here because you’re curious about the process of running a diesel engine on waste vegetable oil gathered from a restaurant?

Well, good for you.

Our guess is that in addition to still having the first nickel you ever earned tucked between your mattress and box spring, you no longer want to contribute to all the nastiness that goes along with America’s dependence on fossil fuel.

Give yourself a pat on the back. We’re conservationists. People who don’t want to use more of this world’s resources than necessary, and we place a priority on getting a little more mileage out of stuff that most people would toss aside. We’re also rugged individualists. People who don’t like to depend on others when they can depend on themselves.

Run a Diesel on Waste Vegetable Oil: A Reality Check

By now, you’ve probably read all of the waste veggie oil propaganda:

"...diesel engines run fine on vegetable oil, just as they were originally designed to; restaurants are dying to get rid of this viable fuel alternative — to them it’s a waste product; burning veggie oil is better for the planet than burning fossil."

As far as we’re concerned, all of that is true.

Going into this, you also need to know that there are no free lunches and no free rides. Yes, you will save money, but you’ll be trading off valuable time out of your life. Compare burning waste vegetable oil in your car to another popular grassroots sustainable energy process: burning wood to heat your house. If you’ve ever cut, split and stacked enough firewood to last through a cold winter, you know what we're talking about. It saves you money out of pocket, but it’s going to cost you some sweat and maybe even a minor flesh wound or two.


There will be food particles suspended in the oil and, before you can burn it in your car, you need to get them out. This isn’t brain surgery, but it can be tedious if you’re doing it the old-fashioned way, pouring the oil through strainers by hand. There are more effective ways, but it will involve buying additional equipment, a pump, hose, spin-on filters etc.

Then there’s the waste. The plastic containers are recyclable, but you’ll have to clean out the containers or risk drawing the ire of the folks at the local transfer station. Ditto for the cardboard. If it’s soaked in oil, they might reject it, which means you’ll be sending it to the landfill.

In addition to the packaging waste, you will also invariably have some oil at the bottom of the containers that are so polluted with charred food that it’s virtually unusable. You’re going to need to get rid of this unless you plan on taking the time to clean it and burn it.

Modifying the Vehicle

You need to modify your vehicle to burn WVO. If you are planning to burn WVO in a car that is under warranty, this will definitely void said warranty.

The best kit on the market is the Greasecar kit. It costs about $1,000, less installation. If you can’t do it yourself, then at $80 an hour, which is what most repair shops charge, you could be looking at more than $1,000 for installation. In fact, Greasecar charges between $1,000 to $1,400 for installation. If you’re driving 15,000 miles a year in a VW diesel that gets 40 mpg, it’s going to take you more than a year just to pay off the price of the kit and the installation.


It’s possible to filter all of the fryer junk out of the oil before you dump it in your car. You’re going to have to change the filters on your car more frequently than you ever had to while burning diesel. This isn’t a big deal, but it is one more step in the process that people who just pull up to the pump, fill up and then drive off, never have to deal with. And if you drive too far with a clogging filter, you could be left on the side of the road facing a $200 tow bill, and there goes some of your savings.

Final Thoughts

It's important to understand that burning WVO isn’t as straightforward as some might lead you to believe. It is interesting and rewarding but will require some work on your part. But, hey, we’re conservationists and rugged individualists. We don’t give up after hearing a little straight talk, right?