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You are in: Lancashire > People > Your Stories > Psst! Want a cheaper fill-up?

Paul O'Gorman

Will Paul still be smiling next week?!

Psst! Want a cheaper fill-up?

Paul O'Gorman's been running his diesel car on a different kind of fuel - and saves £15 each time he does it. So what does he use? Cooking oil - and here's how...


Got a diesel car? Want to save about £15 every time you fill up? How do you do it? Use cooking oil!

It's a lot cheaper than diesel - and there are lots of reports on the internet of diesel cars running on a mixture of cooking oil and diesel.  So if the reports on the internet are true, you could save yourself a packet - but should you believe all you read on the internet?

As an experiment, BBC Radio Lancashire's Paul O'Gorman poured 15 litres of vegetable cooking oil, bought in a supermarket into the tank of a 1999 VW Passat 1.9 Tdi.

But how can a car run on cooking oil?

This is for DIESEL engines only. Petrol engines are a whole other technology and cannot burn vegetable oil.

fuel prices

Can you save money on your diesel?

Diesels CAN run on fuel made from plants. BIODIESEL which is sold on many petrol forecourts is exactly that.

Oils sold for cooking are also made from a variety of plants - corn, soya, rape seed, olives, so they're not that different.

However, those who've tried it say an ordinary diesel engine cannot run on 100% pure vegetable oil, because its too thick and gloopy to get through the fuel pump and injectors.

One way round it is the get the engine converted so the oil is heated to thin it, but its quite complicated and expensive - so for our purposes, we'll leave that to the experts.

The other way to thin it, is to mix it with something runnier like regular diesel. Just mix your vegetable oil into your diesel.

People who are trying this say the easiest way to do this is to run your tank almost empty. Then when you pop to the supermarket, fill up with diesel, and then add the vegetable oil. The drive home mixes it all up nicely.

How much vegetable oil should you use?

These are not my calculations, cos I haven't tried it properly yet - BUT the enthusiasts writing on the internet say you should start with a light blend, and increase each time you refill. That way, if you notice your car sputtering, you know you've hit the limit and should use less next time,

They claim that a 10% vegetable oil blend will work for everyone there should be no noticeable difference in how your car drives.

At 25% vegetable oil in 75% diesel, your exhaust stops smelling like a taxi and starts smelling like a doughnut fryer.

33% one part vegetable to two parts regular diesel - is the heaviest sensible mix for the British winter (the oil gets even thicker in colder weather), but half and half -they say- is a good running blend for the rest of the year. Half-and-half is where the cost savings really show themselves.

How much could you save?

Diesel's anything from 96p to £1 a litre. You can get cooking oil for about 55p a litre. So doing it this way, you save up to 45p per litre.

If you mix it half and half in a car with a 60 litre tank, that's a saving of about £14 per tank. 

If you use waste oil, and filter it as some people are doing, the savings can be even more dramatic, especially if you can get used cooking oil for nothing!

So why isn't everyone doing it?

It used to be illegal. To use cooking oil as a car fuel, you had to declare you were using it, and pay tax - which brought it nearer to the cost of regular diesel - so it wasn't worth it.

Anyone doing it was breaking the law, which is probably why we didn't hear much about it.

But in July, all that changed as Dave Gostelow from Her Majesty's Revenue and Excise confirmed to BBC Radio Lancashire...

Isn't it going to damage your car?

There are many reports on the internet of cars running trouble-free on a vegetable oil mix. Yet there are vehicle experts warning that this is not a wise thing to do.

You have to wonder how often your average mechanics has come across this first hand - as it's been illegal, probably not that often. If you're thinking of trying it, make no mistake that its at your own risk.

So don't just take our word for it. Satisfy yourself that it's likely to work for you.

Internet talk suggests that some cars work well while others don't... its commonly reported that it doesn't work well with cars fitted with a Lucas fuel pump, but with Bosch, there are fewer problems.

If your car in under warranty though, the manufacturers probably wouldn't be very sympathetic should you have an engine or any other problem - which is probably enough to put off most people from trying it in a fairly new car.

Heed the warning that this is still untried territory -  so you might regret it - but if it does work, it could save you a packet.

So how is my car doing? So far, so good, but I'll let you know more next week!

Paul O'Gorman


Some of the world's biggest rock bands have been criticised recently for the carbon emitting, gas-guzzling effects of their world tours, but one band promoter in North Lancashire is doing his bit to tackle the problem... albeit on a slightly smaller scale.
His bands tour in a diesel van.. powered by... cooking oil!

Music promoter Ben Ruth told Tim Padfield in Lancaster about his tour van which is powered by vegetable oil...

last updated: 10/07/2008 at 11:08
created: 15/10/2007

Have Your Say

The BBC reserves the right to edit comments submitted.

jason jackson from Canada
Many people where I live are importing Mitsubishi Delica vans with turbo diesel engines. Some people are fully converting their vans to run on Waste Vegetable Oil (WVO), and some people like me are mixing 20% thru the winter, and increasing to 50% in the summer. Works for me, and my mechanic, who has years of experience with the mix.

Phil Bamford
It's an interesting thought but I have a simple easier idea as explained on the John Barnes show last month(click on via Radio Lancs to listen) Fitting a Government tested Magnetic Fuel saver WILL reduce you fuel bills by at least 10% and can be quickly taken off and re fitted when you change cars. If that's not enough any customer not happy after 3 months gets all their money back.Kind regardsPhil Bamford

j.richmond from accrigton
i;ve been running my cavalier on a 50/50 mix for about 10 months.i say it runs better.isuzu engine better than vauxhall because it has a heated fuel filter for cold starting.

Sam Tana
If you put veggie oil in the tank of a modern diesel car you'll wreck the engine within seconds and cause hundreds if not thousands of pounds of damage, because the engines run at much higher pressure to give smoother performance, and need all the lubrication found in modern diesel fuels.

Nigel from Morecambe
We've been doing this for a while. Our car is an older diesel and I ould think twice if it was a newer, more technically advanced model.

John Knights
I have been doing this for years, (duty paid of course)works well, especially in older TDI series Land Rover engines, the sooner the car industry builds the cars ready to run this way the better

Q. POG, have you saved some cooking oil for erm- cooking?!Top homework, ledbetters sell cans of easy start for £4.99!

Peter W J Morrison
Hi Paul. Glad you've joined us in our green fuel revolution, its ggod to see this being promoted.I got involved with this when I was an undergraduate, my interests took me towards biofuels.I started experimenting, first producing 'Biodiesel' from new cooking oil, then shifted towards using waste fats from chippies as my feedstock. Biodiesel is made by reacting triglyceride (fat) with monohydric alcohol together with a catalyst.After a while I realised I was doing a lot of chemistry (and expense) to produce this fuel. My research moved on to develop a system which simply cleans up and finely filters used cooking fats, this simply means I collect the fats for free and spend a little time, but no cost, to make this into a useful fuel. I have now developed a very effective and simple system, which I try to promote to allow other people to do the same.You mention that using these fuels was illegal, that's not strictly true, it was the fact that the fuels were used without fuel duty being paid that was illegal.I have been doing this since the days when we had to be registered with the Customs and Excise. The government has now started to see sense by allowing small producers to make up to 2500 litres per annum before fuel duty becomes payable.Here’s to many years ‘green’ and virtually free motoring.Regards.Peter W J Morrison BSc (Hons)

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