Replacing the drain plug on the fuel filter (Xantia 1.9TD)

Napoleon · Post by **Napoleon** » 29 May 2010, 17:29

Not a crap description at all, Chris.

Does anyone know why this stat causes a problem when using SVO?

Or to be fair to the car, why SVO causes a problem with the stat?

Xaccers · Post by **Xaccers** » 29 May 2010, 18:17

veg oil eats rubber and other polymers.
I keep the funnel for filling Cassy in my boot in a plastic bag/bin liner, and regularly have to change it as the residual oil is able to seep through the bag.
Remember the o-ring has had 10 years to harden up as well.

Post by **CitroJim** » 29 May 2010, 18:21

Excellent stuff Chris

And there Tim, a repair that costs 5p, literally

Brilliant

Dommo · Post by **Dommo** » 29 May 2010, 18:21

Chris570 wrote:it is removable and fairly easily, just get a small screwdriver and prise it out. i did this on the 1.9td i had, there is a mod to divert ALL fuel through the warmer which is a good idea if running veg oil to help it get thinner.
once you get it open you'll see exactly what to do, you'll need a 5p piece to use in there

sorry for the crap description but you'll see exactly what i mean when you get it apart

I need to do this to my 306, exactly the same layout as this setup. Do you remove the white thing with the thermostat attached and stick a 5p in its place? I'm not really sure what needs doing can't you tell...

Chris570 · Post by **Chris570** » 30 May 2010, 18:52

It's a mod that diverts all fuel though the heater, it is written up on vegoilforum (can't take the credit there)

you cut the white valve thingybob about halfway done and put a stopper (the 5p) in to divert the fuel. the best thing to do (infact the ONLY way to do this is to take it apart and have a good look, you'll see how it all works and how to modify it.

the biggest problem with veg is getting it to the injection pump. contrary to the petrol xantias the fuel system on the TD (not HDI) works on negatvie pressure so the injection pump is sucking the fuel up from the tank, now when the oil is cold it is a lot thicker so the pump has to suck harder so that ANY issues you have with your fuel lines will be highlighted. What it will do is suck air in way way way before any fuel leaks out so it makes it harder to diagnose. The fuel filter housings on these engines are sh!te for leaking so with the added strain of veg oil they are even worse.

How to combat this is really a matter of preference really but the key parts is to either reduce the strain on the IP by lowering the amount of "sucking" the pump has to do. You can do this by either changing the blend of oil you use (more diesel) heating the oil (above mod or heat exchangers) or pumping the oil....

I went for a low pressure (key here is low) lift pump to move the oil along in the pipes so that the IP didnt have to suck as hard so that there was no air being drawn in.

I say LOW pressure (3-4psi) because if you get one say that will pump petrol it will either last for about 2 days or it will push the fuel through too hard and blow the seals on the IP.

A fair bit to read there chaps sorry, just thought i'd give my 2p's worth to running veg successfully

MikeT · Post by **MikeT** » 30 May 2010, 19:43

I don't think it's a good idea and I personally wouldn't advise anyone does this mod as they'll run the risk of overheating their IP.

Secondly, the fuel won't get up to temperature any quicker but it will get hotter.

If you've got air leaks, my advice is to fix them.

Chris570 · Post by **Chris570** » 30 May 2010, 20:15

sorry, i didnt mean to give off the impressions that bodging it would be ok. My point was that veg causes strain on the system and will induce air a lot easier than if you were running diesel.

for those are interested i found the write up (i must confess it wasn't 5p but 1p)

http://www.vegetableoildiesel.co.uk/for ... ?tid=10455

MikeT · Post by **MikeT** » 30 May 2010, 20:30

Chris570 wrote:sorry, i didnt mean to give off the impressions that bodging it would be ok. My point was that veg causes strain on the system and will induce air a lot easier than if you were running diesel.

So why not fix the leaks instead of running the risk of overheating the pump?

Chris570 · Post by **Chris570** » 30 May 2010, 20:48

MikeT wrote:
Chris570 wrote:sorry, i didnt mean to give off the impressions that bodging it would be ok. My point was that veg causes strain on the system and will induce air a lot easier than if you were running diesel.
So why not fix the leaks instead of running the risk of overheating the pump?

it adds a few degrees to the temp of the oil, the point is that the system was never designed to run oil in the cold temps we have here.

Once again i'll say that bodging is not the way to go as you'll only end up doing the job twice. The standard filter system is prone to getting these leaks and do need help with the thicker stuff.

It is up to the individual to decide what they want to do all i'm trying to do here is give my 2p's worth

MikeT · Post by **MikeT** » 30 May 2010, 23:50

I apologise if you feel I was shouting "bodger", that wasn't my intention, it just sent alarm bells ringing in my head.

Again, I'm not making accusations but if the fuel is to be heated by the coolant, it'll rise a lot higher than a few degrees AFAICT.

The coolant in my engine is kept around the 85-90 mark and the fans can usually keep it below 95 if need be but on a hot day, say stuck in slow moving traffic or under heavy engine load, that can easily rise another 10degrees or so. That's assuming the cooling system is in better shape than a leaking fuel system of course.

By all means spread the word of everything and anything beneficial, as you say, it's up to the individual to decide but do expect differences of opinion along the way.

Napoleon · Post by **Napoleon** » 31 May 2010, 09:42

I've read that lengthy thread on vegoil.com, and came to the conclusion that this mod isn't going to do anything to stop the leak from the stat.

I've got the stat out, and the o-ring looks ok to me (but that means little, I suppose).

Napoleon · Post by **Napoleon** » 04 Jun 2010, 13:07

Ok, I'm back on the road again, after a lengthy delay waiting for a spare housing to arrive. £15 off eBay.

So what blend should I try running the car on? I'm talking svo and derv here, no wvo in use at all.

I have a feeling that 50/50 will be ok, but it needs to be a bit more accurate than that, and based on what you other guys do.

Please post your mix.

Thanks for the ideas on getting Xant back on the road where she belongs.

Chris570 · Post by **Chris570** » 04 Jun 2010, 13:22

50/50 will be fine, in this weather 75/25 is easily do-able

Napoleon · Post by **Napoleon** » 04 Jun 2010, 13:29

And that seal in the fuel 'stat?

I mean, I'm sure the car will run on a strong mix of svo, but it's this damned seal that is the focus of my worry.

Penguin · Post by **Penguin** » 04 Jun 2010, 13:34

I run 50/50 in the winter without any real problems. This time of year 75/25 is easily do-able, I am currently 90/10 during this particlar warm spell.