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How to filter vegetable oil for use as fuel

I have wrote an article before about using waste vegetable oil as fuel on a small scale before, but now that I have a Land Rover that has a vegetable oil conversion, I have had to up scale my processing capability as I can now use more of it.

I now use a 2 stage filter process that I have set up in my garage. Its still a fairly manual way of doing it, but it suits my needs at the moment. So lets have a look how I do it.

Stage 1 – Filtering into a holding tank

This is my holding tank - an old water butt! Open the tap at the bottom when I need some veg oil!The first thing I do is to pre-filter the vegetable oil as it goes into my holding tank. The holding tank is a water butt that I thoroughly cleaned out before using the vegetable oil.

I purchased a “Mighty White” mesh filter off eBay that can handle a lot of vegetable oil in one go. The filter will hold approx 15 litres of waste oil and has been constructed with a very fine stainless steel mesh. I have the filter suspended over the water butt, and I pour my waste vegetable oil straight into it. This way I can leave it to filter through overnight.

This is my first stage filtering - 77 micron filter straight into the holding tank (water butt)The “Mighty White” filters the oil down to 77 microns, and removes all the old bits of fish & chips, and anything else they have been frying in the oil! The filter is re-usable, and can be cleaned out with hot soapy water and a soft brush.

Now the oil is in the holding tank, I can use the drain tap at the bottom to decant vegetable oil into a bucket when it is needed for the second stage filtering.

Stage 2 – The final filtering

This is 2nd stage filtering. Note the 3 filters inside each other - 100, 25 and 1 micronNow that the oil is in the storage tank, I can use the drain tap in the bottom to decant the oil into a bucket and then pour it straight into a second set of filters. These are bag filters, and I have 3 of them, one inside the other.

This is my current sock filter set up

  • 1st filter: 100 microns
  • 2nd filter: 25 microns
  • 3rd filter: 1 micron

After filtering to 1 micron, the vegetable oil is poured into clean 20ltr containersEven though the vegetable oil has been filtered down to 77 microns when it went into the tank, the reason I use a 100 micron filter again is to catch anything that might have entered the oil while in the storage tank (water butt).

Filtering vegetable oil down to 1 micron is more than good enough for use as fuel. Land Rover (and most car fuel filters) only filter down to about 5 microns anyway, so 1 micron is good enough for me! You can mix up your sock filters if you want, in the past I have used 100, 25, 5 – as long as you filter down to at least 5 microns you will be ok.

Once the oil has passed through the 3 filters, it collects in a big bin. From there I can just pour it out into a jerry can or a clean plastic container for storage until I need it.

From here I just tip it in the tank when I need it! Easy.

IMPORTANT NOTE: I have a twin tank and heat exchanger system, so the engine is started and shut down on pump diesel, and only when up to temperature will I switch over to vegetable oil.
Even then, I always run some diesel mixed with the vegetable oil in the main tank. I never go higher than 80% vegetable oil mix in the summer, and much less than that in the winter (30-50%). I will never run 100% vegetable oil even with a heat exchanger – Thanks to Trailerfitter in the comments below for jogging my memory to add this to the article!


Not all Land Rover engines are suitable for using vegetable oil. Generally, if your engine is running the Bosch fuel injection pump then you are in the clear. (200/300tdi)

If its a Lucas/CAV pump (Series 2.25/Defender 2.5NA and TD) then you will have to fit a heat exchanger and twin tank set up, otherwise you risk ruining your injection pump.

Note: It is not recommended to use vegetable oil in the Land Rover TD5 or latest “Puma” TDCI engines.

  • Series/Defender 2.25 – Lucas/CAV pump – use heat exchanger/twin tanks
  • Defender 2.5NA/TD – Lucas/CAV pump – use heat exchanger/twin tanks
  • Defender/Discovery/Range Rover 200Tdi – Bosch Pump
  • Defender/Discovery 300Tdi – Bosch Pump
  • Range Rover DT/DSE/DHSE (6 cylinder BMW engine) – Bosch Pump


  1. Hello Matt ,
    I have two series landy’s , one is a series 2A 88″ and the the other is a series 3 109 tempo , I.e . A three door . I would like to convert both to run on used vegetable oil . Kindly advise about the type of heat exchangers that are recommended .
    Reg the twin tanks , why are they recommended ? Should I start with regular diesel and then switch over to the vegetable oil ? We use the CAV pumps on these landy’s.

    The website is temporarily down , hope to get it up and running soon .
    Thank you very for the lovely article with illustrations !


    Omer kaiser

  2. The reason for the twin tanks is to allow start up and shut down on regular diesel. Once the Land Rover is up to temperature you can switch it over to vegetable oil. Have a look here for some further info on my set up:

    The Lucas/CAV pumps use the diesel to lubricate the injection pump, and I believe the tolerances are fine, so using vegetable oil without heating it first tends to “gum up” the pump and cause it to fail.

    You can buy the whole kit to convert your Land Rover from – Comes with the tank and heat exchanger and all the necessary parts to complete the job.

  3. Bit of a mine field this subject. After seeing holding tanks for waste oil that were collected on a commercial scale the amount of water and fish oils in the waste veg oil makes it not suitable for use. I know many use waste oil but if you see it run through a large diesel system the faults show up quicker.

    The lucas /CAV FIPs are not suitable at all for vegetable oil and gum up quickly due to the manner of how the pumps are constructed as you have rightly stated. The Bosch Ve pump from write ups is fine but in reality fail under veg oil running. frm experience I can state this as an expert.

  4. Trailerfitter, yes I agree with you, the oil has to be good quality. My oil comes from friends with seaside cafes, so I know the quality of the oil. They save the best oil for me, and throw away the dirty/fatty oil.

    Something I didn’t write in the article (but will amend it now), is that I always run diesel mixed with the vegetable oil. I never go higher than 80% vegetable oil mix in the summer, and much less than that in the winter. I will never run 100% vegetable oil even with a heat exchanger.

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