(Xantia) Heater Core Replacement Time?

[addo]

I've lost about one litre in five weeks. Can't see any signs of loss via the block, engine bay hoses etc etc. Certainly there's a noticeable coolant smell when the car is running and aircon isn't on.

Also it gives you a blast of moist air on startup.

Would loss rates of this magnitude not respond (permanently) to a leak-stopping product? I'm guessing that's the case. Do they ever develop catastrophic failure? Knowing this detail will help schedule and prioritise repairs.

Hmm... Only standard-issue failures left to experience are strut tops and brake doseur boot.

Regards, Adam.

[Peter.N.]

Hi Adam

You have most of the symptoms of matrix failure. You will usually find that the carpet is wet under the heater - that should clinch it!

If your strut tops are rusty but not rotten, squirt some oil on them periodically, that will stop them getting any worse.

Peter.N.

[ACTIVE8]

It appears that they leak constantly when they are passed it, instead of complete failure, or have some done the opposite?

[handyman]

Addo, it's time to get the spanners out. There is no point in pouring sealants into the cooling system, once the matrix starts to leak, there is only one solution. (Sorry about the pun.)

Book time is twelve hours. It can easily be done over a weekend. In addition to the matrix, you will need coolant & system flush (essential). I also change any dash lamps that are blown or dim.

There is a mechanic in a Citroen dealership not far from me, who boasts he can do it in four hours without stripping the dash out, but I know he cuts corners and a few other things besides.

Handyman

[addo]

Do you have to crack the AC during the process? Not overly worried; just that I'll source a new receiver/dryer beforehand. Present unit appears original.

I've also read about XM evaporator cores leaking, but haven't heard of this on a Xantia.

Won't be cutting any corners. It will be a good time to dust, clean, polish and generally get to know the innards better.

One thing I'm unsure of, is where the scuttle cover's bonded to the screen - how wide is the sealant bead? If I mask the lower glass heavily, can I put a razor edge on a thin spatula and slice through the sealant?

Cheers, Adam.

[handyman]

Hi Addo, from memory, you can do it without disconnecting the AC, but I know it is tight. Last few I have done have been sans climatis.

The dash trim is not sealed to windscreen! There should be a foam rubber filler that sits between the glass and the dash panel. Chances are it is dirty and manky, but will wash up.

Bon chance, mon brav.

Handyman

[CitroJim]

There is a mechanic in a Citroen dealership not far from me, who boasts he can do it in four hours without stripping the dash out, but I know he cuts corners and a few other things besides.

How the chuffin' 'eck does he do that then handyman?

Adam, the job is OK, just incredibly long-winded and tedious. The only really tricky job is disconnecting the matrix water elbow as it can break. Use the patent "DickieG" method of doing it with the cooling system hot and under maximum pressure. Run the engine until the fans cut in and then quickly stop and unclip the elbow, being careful of the scalding water that will spurt out. Replace the O rings on reassembly.

The other thing to remember to do is to remove the plenum condensate drain pipe screws up by the steering rack. Failure to do so will break the drain and you'll then have condensate leaking in and under the carpets.

EDIT: Yes, it can be done without disconnecting an A/C bits. Tight as Handyman says, but the heater box will pull just far enough forward on the A/C pipes for the matrix to clear the crossmember above its aperture.

[handyman]

Hello Jim, thanks for reminding me about the AC drain, as that is the critical area of heater matrix removal without draining down the AC.

As for the mechanic doing the matrix change in record time, as far as I am aware, he manages to do it without complete removal of the dash. I have not seen his work but suspect there is a lot of bending and brute force involved. Maybe he does not refit the dash, going for that lightweight look.

The plastic elbows! I always strip out cold, as I take the view, if they are brittle through age hardening and cavitation, they deserve to break! They can be replaced by getting another set from the breakers yard. It is easy to remove the hoses, as the bonding can be detached, just leaving the elbows to be removed and replaced, using jubilee clips to hold the hoses onto the replacement elbows.


Handyman