# Can I really run a diesel car on cooking oil? **URL:** \ **Category:** Factual Questions\ **Created:** [February 20, 2003, 5:32pm UTC](https://boards.straightdope.com/t/can-i-really-run-a-diesel-car-on-cooking-oil/156358 "2003-02-20T17:32:55Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![owlstretchingtime](https://avatars.discourse-cdn.com/v4/letter/o/958977/32.png) [@owlstretchingtime](https://boards.straightdope.com/u/owlstretchingtime)\ **Post date:** [February 20, 2003, 5:32pm UTC](https://boards.straightdope.com/t/can-i-really-run-a-diesel-car-on-cooking-oil/156358/1 "2003-02-20T17:32:55Z")
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? ---
**Author:** ![yojimbo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/yojimbo/32/232_2.png) [@yojimbo](https://boards.straightdope.com/u/yojimbo)\ **Post date:** [February 20, 2003, 5:41pm UTC](https://boards.straightdope.com/t/can-i-really-run-a-diesel-car-on-cooking-oil/156358/2 "2003-02-20T17:41:30Z")
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 🙂 ---
**Author:** ![yojimbo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/yojimbo/32/232_2.png) [@yojimbo](https://boards.straightdope.com/u/yojimbo)\ **Post date:** [February 20, 2003, 5:44pm UTC](https://boards.straightdope.com/t/can-i-really-run-a-diesel-car-on-cooking-oil/156358/3 "2003-02-20T17:44:10Z")
[Frying squad foils cooking oil car scam](http://www.guardian.co.uk/uk_news/story/0,3604,807299,00.html) > [@](#): > > The Asda supermarket in Llanelli, south Wales, has slapped a ration on cooking oil sales, after astonished internal auditors found that it was selling far more than any other outlet in the country. Customs investigators are also involved in the “sniff patrols”, which home in on any car smelling like a mobile fish and chip shop. > > “It’s a serious offence,” said Bill O’Leary, spokesman for customs and excise, which levies tax on motor oil but not on the version used in saucepans. “By law, all cars on public roads must pay a tax on the fuel they use. Evasion carries a maximum seven-year jail term.” ---
**Author:** ![owlstretchingtime](https://avatars.discourse-cdn.com/v4/letter/o/958977/32.png) [@owlstretchingtime](https://boards.straightdope.com/u/owlstretchingtime)\ **Post date:** [February 20, 2003, 5:57pm UTC](https://boards.straightdope.com/t/can-i-really-run-a-diesel-car-on-cooking-oil/156358/4 "2003-02-20T17:57:03Z")
Cooo! Who’d have thought it. Does it smell different depending on where you get the oil? Eg Curry house, chip shop? ---
**Author:** ![Derleth](https://avatars.discourse-cdn.com/v4/letter/d/b9e5f3/32.png) [@Derleth](https://boards.straightdope.com/u/Derleth)\ **Post date:** [February 20, 2003, 6:02pm UTC](https://boards.straightdope.com/t/can-i-really-run-a-diesel-car-on-cooking-oil/156358/5 "2003-02-20T18:02:35Z")
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. ---
**Author:** ![Floater](https://avatars.discourse-cdn.com/v4/letter/f/dc4da7/32.png) [@Floater](https://boards.straightdope.com/u/Floater)\ **Post date:** [February 20, 2003, 6:06pm UTC](https://boards.straightdope.com/t/can-i-really-run-a-diesel-car-on-cooking-oil/156358/6 "2003-02-20T18:06:48Z")
This is what the [German environment department](http://www.umweltbundesamt.de/uba-info-presse-e/presse-informationen-e/p0100e.htm) has to say about it: > [@](#): > > Diesel fuel made from rapeseed oil holds no distinct advantages for the environment ---
**Author:** ![Alereon](https://avatars.discourse-cdn.com/v4/letter/a/ecd19e/32.png) [@Alereon](https://boards.straightdope.com/u/Alereon)\ **Post date:** [February 20, 2003, 6:24pm UTC](https://boards.straightdope.com/t/can-i-really-run-a-diesel-car-on-cooking-oil/156358/7 "2003-02-20T18:24:33Z")
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. ---
**Author:** ![scout1222](https://avatars.discourse-cdn.com/v4/letter/s/34f0e0/32.png) [@scout1222](https://boards.straightdope.com/u/scout1222)\ **Post date:** [February 20, 2003, 6:52pm UTC](https://boards.straightdope.com/t/can-i-really-run-a-diesel-car-on-cooking-oil/156358/8 "2003-02-20T18:52:35Z")
Check out [www.greasel.com](http://www.greasel.com) 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.