Xantia heater matrix renewal

andmcit · Unread post by **andmcit** » 28 Jul 2008, 13:32

I've removed the whole heater box housing in the past but that must've
been a while back now as I'm damned if I can remember how it was
fastened in!

I ask, as I will need to replace a matrix in my Activa and have tried a
dummy run with an AC estate I'm currently breaking! The dash is out
and the main loom across the dash has been unclipped from its fastenings
and the input feeds into the top of the actual matrix are now visible.

The try out hasn't been a waste of time as I've now reminded myself how
the dash fits and how much needs disconnecting and also how the scuttle
trim is bonded and a lot stronger than the outer skin on the windscreen
laminated glass; I've broken the front screen unstitching the scuttle...

One more thing; as the idea is to unclip the heater box just enough to slide
the matrix upwards out and leaving the AC feed pipes connected how are
they fastened on the engine side; I haven't looked but understand there's
a vulnerable connection here isn't there?

Andrew

Unread post by **CitroJim** » 28 Jul 2008, 14:10

Hi Andrew,

To move the heater box forward sufficiently, there are three bolts and one very important drain pipe.

The drain is reachable from underneath and is held in with two T20 torx screws. The drain pipe will break unless these screws are out.

The three heater box fixings are a long 10mm bolt by the air intake next to the wiper motor, a nut on a stud in about the middle of the bulkhead half way down behind the inlet manifold. It usyall has a plastic clip on the end holding one of the heater pipes and the last one is down behind the LHM reservoir buried in amongst all the hydraulic pipes down there. You need to have the reservoir off to even see it. Then a 10mm long reach socket is needed. This too may have a plastic clip on the end of it in an Activa holding the clutch hydraulic pipe.

Then, once these are out, the whole heater box will slide forward (after removing the two T20 torx screws holding the metal plate over the matrix water inlets) just enough to pull the old matrix out...

Did you successfully disconnect the matrix water connector then?

Unread post by **CitroJim** » 28 Jul 2008, 14:14

Andrew,

Another thing, on a MK1, you'll most likely need to remove the big steel hoop over the top of the steering column as well before the box will come sufficiently far forward. This is bolted down at the foot of the centre console under where the ashtray would be if the dash was still in place.

keep the questions coming, it's still fresh at the moment!

andmcit · Unread post by **andmcit** » 28 Jul 2008, 22:14

I've got the scrapper Xant apart enough that the inside is all but removed
and undone every bolt and nut I can find on the bulkhead believing them
to be dash fasteners; poor memory is a terrible thing, but I've never had
brilliant recollection even when I was a lot younger!!

No, I've not had the dubious challenge of undoing the easy clip heater
pipe mounting joint on the bulkhead yet, so warming the cooling up first
helps then!!?

The car can still be started and run as the engine, hydraulics and cooling
systems are all untouched though the keypad and ignition switch are handy,
they've been removed, as has the main column and the support tube bar
you mention on the drivers' side of the centre console area.

I can get all round the car as I've got it parked on my flatbed car transporter
trailer, wherabouts underneath am I looking for these TORX fasteners?
Is the drain obvious to find!!?

All the best,
Andrew

john alexander · Unread post by **john alexander** » 28 Jul 2008, 22:18

Hi andrew, the one your breaking , does it have a harrison a/c pump by any chance as i need one . regards John.

Unread post by **CitroJim** » 28 Jul 2008, 22:30

Lying under the car Andrew, the drain tube is on the passenger side just above the steering rack and on a flat surface. It looks like a small right angled rubber tube sticking out and has a round metal plate with two torx screws in it. Part of the plate might be obscured by sound deadening. You don't need to remove the tube, just the two screws.

Don't do it when the engine is hot as I burned my arm on the exhaust!!!

Yes, I firmly believe, from what Richard did with mine, that having the engine so hot that the fans are running and maximum pressure in the cooling system really does help the connector apart. Watch for hot coolant spraying out though so wear gloves. Also, if you are doing it on a 2.1TD or an Activa, stuff rag in the open hole(s) of the inlet manifold, just in case coolant splashes into the inlet tract!!!

You can run the engine with the dash right out and all instruments removed, so long as the ignition switch is connected and the keypad connected.

We are also of the opinion that once the job is done, it's a good idea to put Forte Stop Leak in the system as a precaution. That stuff really does work.

The dash fixings are under the rubber bungs accessible once the windscreen scuttle panel is removed and the wiper assembly moved to one side. There is one each on the edges and one in the middle. The two others hold the steering column in and don't need to be removed. The dash fixings are 10mm nuts whereas the steering column ones are 13mm bolts.

andmcit · Unread post by **andmcit** » 28 Jul 2008, 22:32

I'll check for you asap.

AFAIK the system is in full working order though I never did any direct
motoring in it myself; the car is in excellent mechanical order apart from
a blown HG and a snick on third on the gearbox so I don't doubt the
systems' components. I'll ask the previous keeper if it helps!

Andrew

andmcit · Unread post by **andmcit** » 28 Jul 2008, 22:42

Cheers Jim, I'm sure I'll have a clearer picture on things when battle
recommences tomorrow if I have the inclination...

I'll try and remember to take some pictures to help illustrate the task!
Still not looking forward to doing my Activa.

I still can't believe the bonded plastic scuttle broke the outer corner of the
laminated front screen clear off about 50mm up the screen...

as stubborn as whatsit on a blanket!

What did you and Richard use to remove the scuttle trim? Craft knife?

Andrew

Unread post by **CitroJim** » 28 Jul 2008, 22:58

andmcit wrote: What did you and Richard use to remove the scuttle trim? Craft knife?

I was luucky Andrew, I had a new windscreen fitted the back end of last year and the fitter did a poor job of it so it fell off

They can be a right 'mare though, depending on what was used.

I used automotive grade silicone to reseal it. You only need to seal really well from the passenger side edge, across the top of the air intake and about 9 inches beyond.

make sure there is a big lump of "Blu Tak" like putty stuck in the corner just below the trim as well.

Unread post by **admiral51** » 29 Jul 2008, 00:41

i used automotive grade silicone to reseal it. You only need to seal really well from the passenger side edge, across the top of the air intake and about 9 inches beyond.

Why not use the caravan "chewing gum" only costs about a £1 metre and its pretty much bullet proof

If its good enough for Xantia Estate membranes

Colin

Unread post by **CitroJim** » 29 Jul 2008, 07:50

admiral51 wrote: Why not use the caravan "chewing gum" only costs about a £1 metre and its pretty much bullet proof

I tried it Colin but found the 19mm wide W4 stuff I had would not neatly curve around the contours and if you peeled off the backing paper it was impossible to put in place

It sticks so hard and readily it really was quite impossible for me.

In skilled hands though, it would be the most suitable and excellent stuff, just I'm not skilled enough in its use

andmcit · Unread post by **andmcit** » 06 Aug 2008, 20:36

john alexander wrote:Hi andrew, the one your breaking , does it have a harrison a/c pump by any chance as i need one . regards John.

Nope - Delphi pump if this means anything to you...

john alexander · Unread post by **john alexander** » 06 Aug 2008, 21:07

Hi andrew , I think thats the one , are the pipes screwed on with large nuts . the sanden version has a pad fitting with one bolt in the centre . did the a/c work on the car? regards John.

C.J. · Unread post by **C.J.** » 06 Aug 2008, 21:28

Sorry to interrupt the flow here lads, but a relevant question, albeit slightly off topic.

Reading all these tales of matrix failure is quite scary to me, especially as the donor vehicle that I recently obtained my tailgate from was a relatively young 'W' reg 2.0 Hdi in suprisingly good condition, that had been scrapped just because the matrix had failed!

Is this failure inevitable on all Xantia's, and is there any way/additive to the coolant, of preventing it?

Unread post by **CitroJim** » 06 Aug 2008, 21:49

Hi C.J.

Yes, looking at the design of the matrix I think it is almost a certain it'll fail sooner or later, especially in the absence of regular coolant changes and keeping the antifreeze up to strength. They seem to fail on the top plastic to alloy joint.

As regards a preventative measure, yes there is. Put a bottle of Forte Stop Leak in the system right now. My old matrix is living proof that it works rather well. It stopped up my leak completely and the residue of it can be seen in the picture of my old matrix. It did not stop the smell simply as the damage had already been done and the heater plenum was full of crystallysed antifreeze residue which would smell when it got hot.

I once saw that Valeo (the maker of the matrix) recommended the use of Forte with a replacement matrix as a preventitive measure. That was for a Pug 205 matrix that is very similar and fail just as regularly.

Whilst it's a shame to send an otherwise tidy, late Xantia to the car park in the sky because of a failed matrix, remember it's a good days work to swap one and if you had to pay labour to have it done it would not really be economic for many. For us though it's a different story. It takeas a long time and is tricky but quite doable with basic tools, assistance and words of advice from veterans of the job. A new matrix is not expensive at about £55 from GSF, all in.

So stop worrying!