heater matrix

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mrbump
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heater matrix

Post by mrbump »

I am having problems geting my zx to blow out hot air after recently doing the HG. I have propely flusjed the system and bled it up as it says in the haynes manual (using a temporary ' header tank') and closed all the bleed valves until water is only coming out the heater hose valve, but the air is still cold. I did notice that some chafe which looked like some rusted matrix internals didi come out of the bleed hose at one point. Is there any way of checking that the matrix is ok? It was fine before the HG change, and does not lose any water, or smell of antifreeze in the cabin.
Any ideas?
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alan s
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Post by alan s »

In years gone by I have had CXs with a build up of muck inside the pipes of the matrix.
It is usually a case of trying to reverse flush it using the garden hose. If this doesn't work, try using firstly compressed air, again in reverse flow direction and if necessary in a pulsating action. If all else fails, carefully; repeat <b>CAREFULLY</b> poke a piece of fencing wire into the muck if it can be seen or touched within the straight intake/outlet sections leading into/out of the matrix and gently work until a small hole is created through teh muck and repeat the water and/or air flushing. Eventually, it comes out as a big brown solid block set as hard as concrete.
It's easy to test for blockeages by simply disconnecting it from the cooling system and flushing through with a hose.
As I say, this was a common fault on CXs but with these days of premixed coolants/anti-freeze it's not heard of quite so commonly but I have heard of it happening. If it's blocked, that's about the only way I know of to clear it.
Also, do be sure that the heater is open when you fill the system; you wouldn't be the first to have the valve leading to it closed when you refilled and then wondered why the heater won't go (speaking from experience)[:o)] This is also the reason for the long necked filling bottle to be sure the coolant level exceeds the height of the heater matrix when refilling the system.[:D]
Alan S [;)]
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AndersDK
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Post by AndersDK »

Further to AlanS's fine explanation :
Park the car nose up - then run engine idle untill the radiator fan cuts in. At that point give the engine some light rev'ing to have the water pump work out the system. This is known to get the air out the highest point - which would now be the filler neck.
NOTE : Have the heater matrix valve fully open [;)]
AND be sure the engine oil level is OK before you start [8)]
Let the system cool down untill removing the radiator cap is safe - then top up if necessary - BEFORE the car is levelled.
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mrbump
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Post by mrbump »

Anders, I have tried the same procedure you mention with the front of the car on axle stands (and full of oil[:)]) but it hasnt worked. Hot water seems to come out of the valve once it has been revved, but as soon as the revs drop, the water flow stops. I think it is possibly a blockage. This weekend I will direct the garden hose into it, and if that doesnt work i will use 1200psi of jet washer!!
Am I correct in assuming that the water flow to/from the matrix is never interrupted, and that the amount of heat passing into the cabin is dictated only by some flaps moving to allow more/less hot air to pass? Have these flaps ever been known to seize up?
Thanks
alan s
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Post by alan s »

It's controlled by the water passing through the pipes that run in the matrix so no water passing through = no heat coming from.
I'd be a bit wary of the 1200 psi bit in case you blow the guts out of the actual matrix or wear a face full of crappy, rusty water and coolant.
Follow the instructions I gave in the earlier post or you run the risk of ending up with a white stick and a seeing eye dog. [B)]
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Post by mrbump »

Who said that? :0
alan s
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Post by alan s »

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by mrbump</i>

Who said that? :0
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
If we're both talking about the same thing; you I thought.
"This weekend I will direct the garden hose into it, and if that doesnt work i will use 1200psi of jet washer!!"
Alan S [:D]
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mrbump
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Post by mrbump »

Sorry, that was my failed attempt at humour there.
I did try it with the jet washer, but the hose seemed to be more effective anyway. Lots of sludge, flakes of metal and general crappy mess came out, and as you suggested - tried to adhere to my face. But the plan was foiled when I donned a natty pair of safety goggles! ha ha - touche!
It is running a bit hotter now, and I will flush it again this weekend.
Cheers
alan s
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Post by alan s »

Just another point to ad; if the thermostat is catus in your motor, the air temp will be down on what it should be and hence regardless of how clear the flow of water is, it'll only get warm as the matrix just ads to the cooling efficiency of the system.
I got caught with that one on a CX too.
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Post by sooty »

I thought ZX did'nt have a heater valve, only flaps to direct the air flow through the matrix to get the required heat. In other words the heater matrix is at full water flow all the time.
Sooty [:I]
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Post by alan s »

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by sooty</i>

I thought ZX did'nt have a heater valve, only flaps to direct the air flow through the matrix to get the required heat. In other words the heater matrix is at full water flow all the time.
Sooty [:I]
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
You could well be right, but we were also told the same thing about other models on another board which were declared as being gospel until someone turned up with a pic of the valve controlling the water flow.
I've had it said before on other brands too but I've yet to see one that actually has it mainly due to the insulation on the air flaps being of a perishable material and the potential to turn the car into a summer sauna when the insulation drops to bits as they inevitably do.[:I][:I][:I]
Alan S [:D]
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Post by mrbump »

I think it is the matrix, not the themostat because the water that can be bled out of the top bleed screw is boiling hot like it should be (well not quite boiling but you know hat I mean) not just warm. I still supect the controlling mechanism to the matrix a bit. Will give the matrix one more flush this weekend and then try the heater controls.
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Post by oilyspanner »

BX has a valve controlling water flow,ZX matrix is in circuit all the time, I agree with Alan S about the Thermostat though, for what they cost I change em often.
Stewart
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