Can I really run a diesel car on cooking oil?

Apparently in the North of England people are running their diesel cars on vegetable cooking oil. Nothing would surprise me about people up there. They’re still pointing at aeroplanes, but…

There was a BBC demonstration of how this is done. (I am not recommending this – it may well be very stupid)

On the programme (top gear) they showed it was done as follows: Get and filter some used cooking oil (it has to be used apparently) and add turpentine at a ratio of 997/3. Drain the engine of diesel oil, add the vegetable oil and drive away. Appears to run perfectly.

Cost of running car on chip fat about 5p a litre. Cost of running car on proper, taxed diesel about 60p a litre.

Can this realty be true? Is it possible to run a diesel car on cooking oil? If it is, why aren’t we doing so, surely vegetable oil is a cheap renewable fuel?

You can. It smells very bad and you’d have to be very careful about straining the oil.

There are tax issues to take into account. Don’t know exactly what they are but you would be breaking the law just filling up and driving off. You have to pay some form of tax on the oil and then you’re good to go on your smelly way.

All the above is from memory of a Irish TV prog. about the same issue. I’m sure somebody who actually knows something will be along :slight_smile:

Frying squad foils cooking oil car scam

Cooo! Who’d have thought it. Does it smell different depending on where you get the oil? Eg Curry house, chip shop?

It isn’t that odd, really: Diesel is barely more refined than crude, so any engine that can handle diesel will be able to handle something like cooking oil. It all comes down to the (monstrously incomplete) combustion of long-chain hydrocarbons.

This is what the German environment department has to say about it:

One can run a MODIFIED engine on straight vegetable oil, or one can process the used cooking oil into biodiesel, resulting in a pure fuel and some byproducts (glycerine). Biodiesel is cleaner than commercially available diesel fuel processed from oil, so your exhaust isn’t made up of nasty black clouds of crud. My WAG that a doctored cooking oil fuel wouldn’t burn as cleanly or be as safe for your engine as real biodiesel, but I’m not sure.

I don’t have any cites on hand, but googling for biodiesel and any additional terms of your choice should get you good stuff.

Check out for some more information.

I think there was a similar thread a month or two ago, and I posted this link. But a few others posted and provided some other links, too. Try searching that thread out, too.