How to replace a heater matrix/water valve

I've recently replaced my heater matrix on my Mrk 2 Uno turbo last week (I don't think they would be that different) Its a fun job :D I'm sure you will enjoy it just as much as I did.

Your heater problem could be one of two things, the heater matrix ( new from £45 quid - UK) or a coolant valve (£25 quid) you can work out which one it is when you take it all apart later...

Here are some steps you could use to take it apart -

Drain all of your water/anti freeze out of your car (I disconnected the lower radiator pipe to do this)

You may have already found the inlet and return pipes connected to your heater matrix, you will need a flat screwdriver to remove the jubilee clips that secure them.

If you look just forward from the coolant valve you should find a 4 pin connector, this is the power feed to the fan, you will need to disconnect this. The same cable will also have to be disconnected from the resistor block (the fan speed selector on the front of the center console) Although its much easier to do this when the heating system is on the car floor.

The front of the center console is attached to the dash in 3 places, half way up on the left / right hand side and also at the top, under the ashtray.

On the LHS of the center console you will find a screw which is connected to a bracket that is also attached to the plastic surrounding your glove box (unscrew the complete bracket assembly from both sides as this will make it easier to remove it all later).

The RHS bracket supporting the center console is much the same as the left, 2 screws hold it in place, these will also need to be removed.

The last screw that will need to be removed is under the ashtray, I actually removed the ashtray and the clock/accessory button block from the center console to gain a bit more space to work with.

Looking back at it now, it would have been so much easier if I had taken the gear lever off, this would have created a load of extra space to lower the heating system from the bulkhead...

Once you've done all this there are 4 nuts that need to be unscrewed that hold the heating system onto the bulkhead, the bottom 2, followed by the top 2. After that the unit is free to be removed, although when I went to take it out it took some muscle as it had been fixed there for 19 years...

Now its physically detached from the car have a coffee break :)

If the fan works, then there is NO need to take the fascia off of the heater system :D I say it like that because its a real pain to put it all back together again...

Looking at the heater matrix, the coolant valve is attached to the bottom with 2 studs with nuts. You will need to remove these and lift the valve off the matrix so you can see inside it. Once you have done this, operate the dial on the front of the center console to see if you can see the valve opening and closing, if the valve fully opens and closes then we can move onto the next step.

Removing the heater matrix its self is simple enough, although with mine I found that there was a piece of plastic that I had to carefully prise up in order for the matrix to slide out. when I went to clean mine with an air liner it literally turned into dust, these units aren't supposed to be so delicate, if you find that yours is like a chocolate tea pot :D just throw it away... When i ordered my new matrix, it came with a coolant valve already attached to the unit :) I did not know this at the time and went ahead and bought a separate one (this had to be sent back) (y) so make sure you check with your supplier before ordering.

Once you've got your new heater matrix, its really just a simple case of putting all these steps into reverse. Its really important that you make sure that you do your jubilee clips up tight and when its all been put back together and you've topped your car up with the correct amount of water/anti freeze that you let the car run for about 20 mins so you can check for leaks :D

Hope I've been able to help you, good luck (y)
 
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capers626

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Sep 2, 2007
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111
Hi Funkstar!

I'm just in the process of removing the heater radiator from my 1992 Mk2 Fiat Uno and found your guide very useful :D.

I've removed the screw under the ashtray but can't find all of the nuts which hold the heating system to the bulkhead. I have unscrewed two of them (not sure if classed as top or bottom?) but can't see the others, hopefully the photos will shed some light on where I need to look! :confused:

All the best,
Andy
 

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capers626

Donated
Joined
Sep 2, 2007
Messages
111
Hi Funkstar,

After some further investigation I've managed to find the other nuts to remove the heater, certainly tucked away well out of sight and a bit of a pain to reach though one was missing (on the driver's side).

It looks as though the heater radiator was a replacement for the original one as it has the classic breakers' yard red paint on its side, along with the price! :D

All the best,
Andy
 
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