Run a Diesel on Waste Vegetable Oil (WVO)

Active oil splash in white background
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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’ew concerned, all of that is true.

But 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.

Run a Diesel on Waste Vegetable Oil: Things to Keep in Mind

First, if you make a deal with a restaurant to collect their oil, you need to do so in a prompt, professional manner. In my case, the restaurant had little storage space and was eager to get rid of their waste oil when they had a few containers filled up, lest they get cited for having it around in the event of a health department inspection. So when the manager of that fine establishment called, she expected me to get over and collect the oil, pronto.

Next, you have to store the oil. I have two clean 55 gallon drums in which I store my filtered oil, but the five-gallon containers I get from the restaurant get stacked up in the corner of my garage until I get around to the next step. Which is...

Filtering. 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 like I do it, 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. My oil is given to me in five-gallon plastic containers inserted in cardboard boxes. These 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 too, unless you plan on taking the time to clean it and burn it.

Run a Diesel on Waste Vegetable Oil: 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, first off, I think you’re out of your mind, and second, 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 - $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.

Run a Diesel on Waste Vegetable Oil: Maintenance

It’s possible to filter all of the fryer junk out of the oil before you dump it in your car, but for some reason, I’m never able to. So 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. (This happened to me). And there goes some of your savings.

Run a Diesel on Waste Vegetable Oil: 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?