Disco 2 Bio diesel

After extensive research, I’ve decided to start using bio diesel in my, new to me, disco td5. I ran my 300 tdi on it for 6 years without too many problems. I know the td5 is a different engine, but the only problem I can see with running it on bio is, any natural rubber parts or seals in the fuel pump, filters or injectors, (high pressure pumps), might degrade. I had to have the fip rebuilt with viton seals in my tdi because it started dripping.
Are all the fuel delivery components built with synthetic rubber on a 2003 td5?

It has been said in many places that the Td5 engine is not suited to biodiesel but hopefully someone will come forward with facts rather than opinions.....

What i can tell for sure is that on all the VWs and Skodas i've seen which were equipped with PD(EUI) engines(which the Td5 is as well) there was a label on the filler flap "DONT USE BIODIESEL" ... I'd not take the chance myself cos if the rebuild of a FIP with seals is cheap 5 EUIs for the Td5 are not

That’s the trouble, there are lots of opinions, but very few facts.
While doing my research, I found several articles and posts from people who have actually run the td5 for long periods, with no trouble.
I didn’t find any from people that had actually used bio and had trouble with the td5.
I think as long as I’m meticulous in making the fuel, which I am, the only problem I’ll encounter is any natural rubber parts or seals rotting.

It’s not the seals that are the problem,it’s mainly to do with the viscosity of the fuel as opposed to pump diesel,and that the fuel pump and injectors run at such fine tolerances said parts could be put under more strain.I was always told if it’s mechanical pump engine it will run on anything,common rail=fail.
However,I did run a Citroen berlingo hdi on bio diesel for many months before I changed vehicles at work and it did it no harm in that time.

andy85 said:

mechanical pump engine it will run on anything,common rail=fail.

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though the Td5 is not common rail

andy85 said:

It’s not the seals that are the problem,it’s mainly to do with the viscosity of the fuel as opposed to pump diesel,and that the fuel pump and injectors run at such fine tolerances said parts could be put under more strain.I was always told if it’s mechanical pump engine it will run on anything,common rail=fail.
However,I did run a Citroen berlingo hdi on bio diesel for many months before I changed vehicles at work and it did it no harm in that time.

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Viscosity of good quality bio diesel is the same as pump diesel, unless it drops to a certain temperature. I could run my 300tdi on 100% bio, down to about - 6 or -7. Then I used to put 50% pump derv in.
With the td5, I wouldn’t risk running it on bio at anything less than + 2 or 3.

Can't say I've run personally run bio in a TD5, but it isn't a secret that unit injectors are much more tolerant of good biodiesel than ultra modern CR engines are, so it is acceptable to run 100% bio in the warmer months - as long as it is good quality, and as you're making it yourself keeping an eye on quality is easy, all the myths and no no's generally come from people making and running crappy biodiesel. In an ideal world it should come out a light sunflower oil colour, not hazy when cold, no film layer or sediment after sitting a while, pass through a 5 micron filter leaving no residue and be PH neutral. Dark bio (which I assume you have if you make it with WVO), similar to extra virgin olive oil in colour when finished, but following the checklist will be more than acceptable in a 300tdi, but after a few years the injectors of a TD5 might be less happy if you often run it neat, especially with lots of town driving.

And as an extra thought, looks like you have an anaerobic digestion site in Halstead, so there is probably some capacity locally for someone to actually pay you for your waste glycerine, unless you already are!

You would probably want some good glow plugs when it’s chilly out but other than that just change the fuel filter more regular

Thanks for that advice. I already filter my bio down to 5 micron, but will filter it down to 1 for the td5. The stuff I've been churning out is the colour and clarity of lager. Just spent a few hours on the vegetable oil diesel forums and it seems quite a few people run TD5's on properly made bio diesel with no problems. I think the confusion stems from people mixing up bio diesel and SVO, straight vegetable oil?
Good news about being able to sell my glycerine! thanks for the heads up.

It should run well then, sounds like you're making good stuff!

Properly made bio is fine iv run bio and svo on our old Nissan terran 2.7 as you say filter down to 1micron and if its as good as you say I don't see any problems in using it. The terrano would run on anything I put in it. I don't think a td5 would.

biketeacherdave said:

Properly made bio is fine iv run bio and svo on our old Nissan terran 2.7 as you say filter down to 1micron and if its as good as you say I don't see any problems in using it. The terrano would run on anything I put in it. I don't think a td5 would.

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Yes, I put stuff in my tdi a few times, that I knew I shouldn’t, but it still run ok. I won’t take such chances with the td5. I’ve ordered a whole load of new filters for my waste vegetable oil and bio diesel, plus, I will dry and polish it for an extra hour if need be.

A chap on here called Shifty ran his td5 on special brew for many years

Shiftster where are you these days?

Ok, here’s an update.
Although the td5 loves bio diesel and runs great on it, there are a few things to bear in mind. The td5 has quite a few rubber seals that thebio will degrade. Non return valve in the fuel filter housing, seals in the fuel erasure regulator and injector seals. As far as I know, you can’t buy these viton versions of these seals.
As a result, I’m not going to use bio any more. Anyone want to buy a processor?