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MG MGA - Heater matrix and valve

I'm a bit of a novice, so be grateful to check if my thinking is correct.
I removed my radiator for recoring and decided to flush the engine. I have a thermostat fitted, so thought that if I connected my hosepipe to the pipe coming out of the heater (not valve side), I would be able to flush water through the heater, round the engine, and out at the lower radiator connection.
But when I switched the garden tap on and returned to car, water was spouting out from every orifice of the heater box. I think, that the heater valve at the other end is blocked and so the water had nowhere to go and I assume the mains pressure has blown the heater matrix.

My questions please are:
1. Is replacing the heater matrix a simple case of opening the box and switching it with a new one?
2. Is it common for the valve to seize up and should it be a simple case of out with the old and in with the new? (I ask because I never use the heater, so would rather leave the valve in situ until the winter if there could be problems delaying me getting the car back on the road)
3. Out of curiosity, could the matrix been suspect already or was it my enthusiasm with the hose pipe? I was not losing any coolant and of course the heater is not isolated at both ends.

Many thanks, Graham
Graham V

I would inspect the damage more closely. It is probably only leaking at one point, and you might be able to resolder it.
Art Pearse

Thanks Art. You are quite right. I have it out now and there is a leak from the tank which I will ask the company who is doing my radiator to fix.

But am still not decided if I should change the heater valve. It "moves" on the outside ok, but the passageway through is definitely blocked. Bearing in mind I never use the heater, I am just a bit nervous that I may create more problems for no real benefit ( eg if valve is stuck coming out or new one won't fit or seal properly.
The correct answer is to replace it I know, but I would happily leave it alone if there Is any history of problems with it's replacement.

Thanks, Graham

Graham V

The guy to go to for a new heater valve is eBay seller ashley hinton item

http://www.ebay.co.uk/itm/251946467978

as he's the guy that actually makes them and has to stand behind the quality he delivers !

Mine failed in leak mode and I fitted the new one last night. The thin collar to which the rubber seal in the valve seats had corroded away - looked like new on the outside.

The trick tool is a 7/16 obstruction spanner which makes this a ten minute job



dominic clancy

Dominic
Thanks I have ordered one. I have the valve out and the inside is jammed rock solid with a whitish gunge (see pic)!
Not sure what it is. Could it be from a PO's attempt to fix a leaking radiator with a bottle of sealer or oatmeal maybe? The radiator had repair welds on it so there was obviously a leak at some stage.
I am frightened that all the channels are clogged up with this. I guess I will need to try and flush with a hosepipe and hope that clears it all out, or else it may need to have the head removed.
Certainly don't want to fit the newly cored radiator and fill that with the gunge.
Oh dear, looks,like I may have taken on more than I realised, but I guess I have at least found the cause of my overheating!


Graham V

This thread was discussed between 04/06/2015 and 06/06/2015

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