Jonathan Platt owns his own restaurant. That means he has plenty of leftover cooking oil. Two years ago, he found out he could use that oil to run his diesel pickup truck. The oil from the restaurant is heated and filtered and pumped into the truck from barrels stored in a friend's garage.

"When you run on fryer fat, you actually start the car on diesel, run it for a few minutes on diesel, and shut it down on diesel. But you drive around all day on vegetable oil," said Platt.

Consumer Reports converted a diesel Volkwagen Jetta with a kit you can buy on the Internet.

"This is a normal diesel engine in this Jetta. What we've done is in the rear of the vehicle, we've put a separate fuel tank that holds the french-fry oil. That is transported to the front through these heated lines that use the actual engine heat to heat it. It comes through the filter, which is also heated into the valve," said David Champion of Consumer Reports:

Testers put the vehicle through its paces on the test track and on the highway. It turns out the Jetta runs just as well on cooking oil as it does on diesel fuel. As for fuel economy...

"It goes as far on a gallon of french-fry oil as it does on a gallon of diesel. But, of course, the french-fry oil is a lot cheaper," said Champion.

Consumer Reports gets vegetable oil free from a local diner. Most restaurants are glad to get rid of their leftover grease and will likely give it away.

Platt said he is saving about $6,000 a year. But it is not a totally free ride.

"You do have to go pick it up. You've got to bring it home. You've got to warm it and filter it. That's it. But if you're driving a large vehicle like I am, a big Ford pickup, or even a Mercedes diesel or a Volkswagen and you want to save money, there it is," said Platt.

If you are interested in converting your diesel car to run on vegetable oil, the kits are available. Click on this link: greasecar.com

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