Rudolf Diesel designed his engine to run on vegetable oil. You can
still do it today, but some modifications to your diesel vehicle
will be necessary (it’s not possible with petrol vehicles).
Veg oil is too viscous to use directly in an unmodified vehicle,
so there are two ways that viscosity can be reduced:
removing glycerine to make biodiesel (see biodiesel
factsheet), in which case no conversion is necessary
by converting the vehicle to use straight oil (which reduces viscosity
by pre-heating the fuel)
can be used in any diesel vehicle, and mixed with mineral diesel
in any ratio.
Straight vegetable oil should not be used in an unconverted diesel
vehicle, due to its viscosity, and the fact that the glycerine content
may cause ‘coking’ of fuel injector heads and possible
It’s perfectly legal despite the reports of arrests in Wales
for driving on veg oil. They weren’t paying road fuel duty
on the oil. BUT since June 07 there isn't any duty payable for anyone
using less than 2500 litres.
are the benefits?
oil is a biofuel, and as such is virtually carbon-neutral. This
means that the carbon dioxide (CO2) released
when the fuel is burnt is absorbed by the plants that will provide
the next crop of oil. As CO2 is the main greenhouse
gas, switching to biofuels can help to slow down global warming.
Emissions are cleaner too – sulphur is eliminated, and a range
of other pollutants are reduced dramatically (including particulates,
carbon monoxide, and unburnt hydrocarbons). Further benefits include:
requires less energy to produce; doesn’t have to be transported
such large distances; renewable resource; non-toxic; and biodegradable.
These environmental benefits also apply to biodiesel, but if you’re
sure that your car is worth a conversion to be able to use straight
vegetable oil, this is a more environmentally-friendly option, as
there will be none of the problems associated with the waste from
the biodiesel production process.
can I do?
With a petrol car, nothing – veg oil is for diesel vehicles
only. To find out which cars can be converted, see Diesel
You can buy cooking oil in supermarkets, although we don't recommend
virgin oil for environmental reasons. Goat
Industries sell cleaned-up used oil in bulk (oil drums).
The 2 main pump manufacturers in the UK are Bosch and Lucas. To
run on veg oil a Bosch pump is preferable. Lucas pumps have a ‘paddle’
mechanism which can’t cope with the heavier veg oil. A good
mechanic can swap a Bosch pump for a Lucas.
An extra tank is added for veg oil. You start with diesel, then
switch to veg oil when the engine is hot, and it is continually
heated via a heat exchange system. Before stopping, switch to the
diesel tank again so that there will be mineral diesel in the fuel
line when you come to start your car again. Cost installed c. £800.
DIY kit c. £400.
simple one-tank method
simpler – you don’t have to remember to switch to mineral
diesel near the end of your journey, and veg oil and mineral diesel
can be mixed in the same tank. A simple one-tank conversion involves
pre-heating the oil before it gets to the cylinders, and is only possible with indirect injection vehicles (D, TD, not DI, TDI, HDI, SDI etc), because they have a separate chamber for atomising the fuel before it reaches the pistons, so cold starting on veg oil is fine; also, a new,
wider fuel line is installed between the fuel tank and the heat
exchanger, because of the extra viscosity of vegetable oil. Cost installed c. £600.
Elsbett one-tank method
German kit with a few installers in the UK. They have designed an
engine where veg oil is the fuel and the coolant, so it gets continually
heated. When starting from cold, there is an electrically-heated
jacket on the fuel filter. They say no used oil. In a conventional
diesel engine, fuel is initially sprayed onto a heater plug at the
top of the chamber (which is why you have to wait a few moments
for the plug to heat up when starting a diesel engine); in an Elsbett
conversion, the heater plug stays on until the engine is up to temperature.
Cost installed c. £850-1300, depending on vehicle. DIY kit
c. £550-750. More difficult than the other two conversions
- a job for experienced mechanics only.
In June 2007, the road duty for biofuels was removed for anyone
using 2500 litres or less. Contact HM
Revenue & Customs for advice.
- information, books, links, courses etc.
of this factsheet (pdf)
yes you can
run your (diesel) car on this stuff - but you'll have to convert
your vehicle to avoid damage due to its extra viscosity
all the kit
required for an Elsbett conversion
of a Citroen ZX
End to John O’ Groats: Daniel
Blackburn, seen here beginning his journey to promote veg oil
motoring. He filled up with cooking oil bought from shops on the
one-tank conversion involves the installation of a slightly larger
diameter (because of veg oil's viscosity), insulated fuel line