Xantia Desire TDI 1.9 heater matrix with a/c

petefa · Post by **petefa** » 01 Dec 2004, 03:57

Hi, I am getting the same symtoms that cost me £700 at a citroen dealer less than 2 years ago.
There is only luke warm air coming from the centre vents, all of the others are cold.
The dealer said that the heater matrix was blocked up and had to be replaced. 9 hours labour as the dash had to be removed!!
Now the question I have is, can the heater matrix be reverse flushed to dislodge the blockage and is there a simple way?
Would holts rad flush work?
I reallly do not want to spend another £700

I have reversed flushed the system, by sticking a high pressure hose into the expansion tank, and got a load of red coloured water (rust?)coming out of the bleed screws, (heater metrix, some T-pipe piece near the expansion tank and the one on the thermostat housing, did I get them all?)
But this has made no difference. I have have the servicing done, so wouldn't the antifreeze be tested to make sure that rust could not build up?
Do I have a claim against the dealer?
Any help would be welcomed!
Pete
petefa@hotmail.com

fordsone27n · Post by **fordsone27n** » 01 Dec 2004, 15:29

Is the engine temperature running correctly at about 80c? I've just replaced the engine thermostat in mine and its made one hell of a difference to the efficiency of the heater. Prior to this the engine temp stayed right down at 60c, and thus the cabin temperature was, at best cold! I cant believe the matrix would sludge up this quick, it's not like you fill the rad from the nearest ditch these days is it.
Might not be the problem but worth checking before shelling out.
Adrian

PeterMann · Post by **PeterMann** » 01 Dec 2004, 16:50

Yes. A sludge blockage can theoretically be dislodged by applying water pressure to one side of the heater matrix and leaving the cap off the header tank to let the extra water escape. The risk that needs to be controlled is that the heater matrix is fragile to pressure, so you will need to limit the applied pressure to (say) 10 psi. (the relief pressure on the header tank [23psi]is too high for the seals on the heater matrix, so always use an anti-boil glycol fluid to keep the normal running pressures down)
I cut the rubber heater hose on my Xantia before it dove behind the engine, and then later sealed it with a plastic 3/4inch agricultural ball valve and 2 hose clamps (and keep a spare $5 valve in the boot, although I'm not expecting it to fail). With a ball valve on both sides of the heater matrix, if it ever does start to leak again, I can stop the leak in 30 seconds and keep on travelling.

petefa · Post by **petefa** » 02 Dec 2004, 00:13

Thank you for the replies.
Yes the temp is at 80 and I even removed the stat, to see if that made any difference.
The info about the pressure sensitive matrix is most welcomed.
I will be trying the reverse flush this weekend, and so will keep you informed.
[:D]

petefa · Post by **petefa** » 04 Dec 2004, 21:29

Yahoo!
reverse flushing the matrix has worked, I now have nice warm feet!, lol
This what I did, a bit fiddly, but worth saving £700 for.
I cut the matix oulet pipe roughly in the centre of the horizontal, part, with the intention of fitting a coupling afterwards.
I got one piece of 75mm long, 19mm diameter brass pipe with 3mm wall, (very important this). I then chamfered each end to about 30 degrees, to make it easier to fit the now, two pipe ends, onto afterwards.
A piece 300mm long chamfered the same at one end.
Disconnect the black plastic air turbo pipe near the air filter and tie it out of the way, gets in the way, dam thing!
1 very long screwdriver or M7 socket with a long extension bar to tighten the jub clips up.
I disconected the matrix inlet pipe at the engine end, (don't forget to get 3 new jub clips, 27-30mm, and then inserted the long piece,(chamfered end), into the outlet pipe from the marix. fit the hosepipe to this and reversh flushed it, (see warning about pressure above in previous post).I then used this same pipe with a funnel, to pour directly, some antifreeze into the heater matrix, until it came out of the inlet pipe.
I then used the 75mm and two jub clips to connect the two pipe ends back together and the last jub clip to refit the inlet pipe to the engine.
Bleed the water system as per normal, ensuring that the correct amount of antfreeze is put back in.
About 3 hours work, lots of cursing, due to the small space available, and then a large smile when it works!