Heater matrix

[loogie1]

Accelerating from the lights and pop went my heater matrix...filling my passenger footwell with coolant. For now I have bypassed the heater matrix, but at some point I am going to have to investigate and effect a repair, has anyone on this forum had this experience before and can advise st to what to expect and or possible repair options. Thank you in advance.

[Brianmoooore]

Are you sure it's the matrix? These rarely fail, and from your description it sounds like you may have the fairly common failure of the electric heater valve, which plenty of us have experienced.
There was a recall several years ago regarding a potential cause of this. The problem was the coolant bottle pressure cap, creating excess pressure in the cooling system. The replacement cap has a yellow disc on its underside instead of the black one on the original.

[loogie1]

Are you sure it's the matrix? These rarely fail, and from your description it sounds like you may have the fairly common failure of the electric heater valve, which plenty of us have experienced.
There was a recall several years ago regarding a potential cause of this. The problem was the coolant bottle pressure cap, creating excess pressure in the cooling system. The replacement cap has a yellow disc on its underside instead of the black one on the original.

Thank you, I will have a look at the underside of the pressure cap. So potentially I will only need to replace the electric heater valve and maybe the pressure cap. Once again thank you very much for your time Brian.

[Bonymaenjack]

My original leak was from the valve but whilst replacing it I noticed weeping appeared from the heater matrix so as the job is a bit of a pain I replaced both items , Be prepared for some swearing and unnatural body positions

[HenryM3]

Can’t help but ask are BMW now selling heater valves. Some years ago mine failed/leaked and they were NLA. I was told that if enough people asked for one another batch would be made. Two years later I got a letter from bmw asking if I still wanted one. I was very impressed, car would have been about 25 years old then.

[loogie1]

My original leak was from the valve but whilst replacing it I noticed weeping appeared from the heater matrix so as the job is a bit of a pain I replaced both items , Be prepared for some swearing and unnatural body positions

Thank you, I am 6ft4 so will look forward to that!

[loogie1]

Can’t help but ask are BMW now selling heater valves. Some years ago mine failed/leaked and they were NLA. I was told that if enough people asked for one another batch would be made. Two years later I got a letter from bmw asking if I still wanted one. I was very impressed, car would have been about 25 years old then.

That’s a bit concerning. I will let you know how I get on.

[Brianmoooore]

You need a non leaking valve, but not necessarily a working one. It's a relatively simple job to repair a leaking valve into one that holds water, even if it then no longer works.

[HenryM3]

There must be another valve/substitute out there in the big wide world??

[Brianmoooore]

There must be another valve/substitute out there in the big wide world??

Quite possibly there are suitable valves out there, but the problem is connecting that valve to the existing pipework. The existing valve has a flat flange/ O ring connection to the heater matrix at one end, and the other end is actually the stub pipe that projects through the bulkhead.
The only purpose of the valve is to ensure that the heater produces absolutely no heat when adjusted to fully cold, not to adjust the temperature in any way, except in very rare cases where climate control was specified.
As those of you who run there cars on LPG will know, the vaporiser has to be plumbed into the cooling system to provide heat for the boiling of the liquid propane in the fuel tank. This is usually done by connecting tee pieces into the heater hoses and running the vaporiser in parallel with the heater matrix, but this reduces the flow through the heater a little and consequently its maximum output.
To overcome this problem on one of my E30s, I connected the vaporiser in series with the matrix, positioning it in the return pipe from the heater. This restored the heater maximum output, but required the electric heater valve to be disabled, leaving it permanently 'on'. This meant that the matrix was still fully hot , even when the heater was set to produce cold air only.
There was no detectable warmth in the heater output, other than a short blast of slightly warm air when the fan was first switched on.

[RTTBMW]

Replacement BMW heater valve is £155 plus vat. They class it as a sealed unit!

Regards

Richard

[HenryM3]

Mine was £75 that was 6 years ago, to be fair mine lasted 25 years so I can’t complain. I have spent very little money on parts for the m3 as most things are repairable.

[Brianmoooore]

They class it as a sealed unit!

BMW and other manufacturers of all kinds of things class lots of things as sealed units, especially electrical modules, It's partly a health and safety/liability thing and partly because they make more profit out of a complete new part rather than going to the trouble of stocking cheap bits of parts, although BMW are much better at supplying bits than most other car makes.
Plenty of parts can be opened up and repaired if you know what you're doing, and if you don't, there's usually plenty of help on line.

[loogie1]

There must be another valve/substitute out there in the big wide world??

Quite possibly there are suitable valves out there, but the problem is connecting that valve to the existing pipework. The existing valve has a flat flange/ O ring connection to the heater matrix at one end, and the other end is actually the stub pipe that projects through the bulkhead.
The only purpose of the valve is to ensure that the heater produces absolutely no heat when adjusted to fully cold, not to adjust the temperature in any way, except in very rare cases where climate control was specified.
As those of you who run there cars on LPG will know, the vaporiser has to be plumbed into the cooling system to provide heat for the boiling of the liquid propane in the fuel tank. This is usually done by connecting tee pieces into the heater hoses and running the vaporiser in parallel with the heater matrix, but this reduces the flow through the heater a little and consequently its maximum output.
To overcome this problem on one of my E30s, I connected the vaporiser in series with the matrix, positioning it in the return pipe from the heater. This restored the heater maximum output, but required the electric heater valve to be disabled, leaving it permanently 'on'. This meant that the matrix was still fully hot , even when the heater was set to produce cold air only.
There was no detectable warmth in the heater output, other than a short blast of slightly warm air when the fan was first switched on.

Thank you once again Brian, I still haven't got around to the job yet due to covid-19, and now summer, but mostly my poor health. Repair to a non-leaking valve it is then.

[Brianmoooore]

There must be another valve/substitute out there in the big wide world??

There's been progress on this! See my last post in this thread. viewtopic.php?f=2&t=279429&start=35

[Sanchez]

I changed the large 30mm oring out to stop the leak and replaced the 2 17.12mm ornings. All done and leak free. My threads on the zone Facebook page as my flickr pictures don’t seam to work here.

[HJ1981]

I am about to pull the dash, as well as the entire heading/aircon unit and fix some broken plastics for the flaps.

I found this:

https://www.specialclassicparts.de/epag ... ungsventil

So i would be replacing that O-ring for the valve, i am not affiliated with them, but there are signs that there was a leak somewhere down by the heater valve (there are dried coolant spots here and there).

[Brianmoooore]

https://www.specialclassicparts.de/epag ... ungsventil

I suppose it's a 'one stop solution', but for two O rings and four small nuts and bolts it's a bit expensive. You can buy a box of 400 O rings and a similar number of small nuts and bolts for little more.

[loogie1]

Looks like the valve has popped off ! I take it the black return pipe can be removed to repair.

[loogie1]

So it looks as though I need a set of four nuts and bolts to reassemble and inspect / replace the o-ring?

[loogie1]

https://www.specialclassicparts.de/epag ... ungsventil

I suppose it's a 'one stop solution', but for two O rings and four small nuts and bolts it's a bit expensive. You can buy a box of 400 O rings and a similar number of small nuts and bolts for little more.

Do we know the dimensions of the nuts and bolts and o'rings. See if I can source them elswhere. westfiled fasteners seems a possible source. Thank you.

[flybynite]

Try Bearing Boys

https://www.bearingboys.co.uk/Orings-1050-c

Use them a few times for specific sizes of O-rings.

[loogie1]

Thank you

[HenryM3]

If memory serves me right I replaced mine because the diaphragm inside was perished. Can someone explain what roll that plays and if there is a replacement available. I’m sure I still have the valve in a box of bits. I’m sure I replaced mine because I had permanent heat or no heat. Can’t remember.

[Brianmoooore]

If the valve has failed (or is modified to be) permanently open, the heater matrix will be always heated, but, the heater adjusts its temperature output by blending fully heated air with cold, unheated air, except when the knob is within a few degrees of fully cold, when flow to the matrix is cut off.
If the flap in the heater box is in good condition, the output from the heater should be almost as cold as the incoming fresh air, even if the matrix is still being heated.
I ran a LPG converted E30 like this for a couple of years, and was quite happy with the cold air performance of the ventilation system.
Conclusion: If your valve diaphragm is damaged, an acceptable (and almost no cost solution) is to remove the entire top of the assembly and replace it with a flat plate and gasket/O ring.

[HenryM3]

Cheers for that, I could have saved myself some money. Last question on the subject, does what you just said apply and work if there is a/c fitted.

[Brianmoooore]

It'll work with air con. The only set up it won't work with on an E30 is the rare climate control option.
The top half of the replacement valve supplied by BMW looks nothing like the original, and I'm sure it's an industry standard valve fitted to the BMW bottom half, and I'd estimate its price at about £20 - £30. Just needs to be identified and a source found.

[Tzantushka]

The top half of the replacement valve supplied by BMW looks nothing like the original, and I'm sure it's an industry standard valve fitted to the BMW bottom half, and I'd estimate its price at about £20 - £30. Just needs to be identified and a source found.

Some input from my recent experience...
Brian is spot on - here's a comparison of the two heater control valves (my car is an '88 model - aluminium heater hose, with A/C).



The old heater control valve was original but working.
If I had my time again I would have done this to avoid buying a new valve as part of the heater core replacement:
- remove and drill out the rivets in the old valve
- check the diaphragm is still serviceable
- replace the o-rings as above
- reassemble back together with the threaded bolts

Avoids the mega- £££ with a dopey looking new valve.
Reduces the risk of the rivets giving way and pissing coolant everywhere (OP's failure mode)
If the diaphragm is going to give up the ghost at least it will fail in a contained manner (new o-rings and bolts)

Sigh - lessons learnt.

[HenryM3]

+1 if only my pension would inflate as much and quickly as these valves.

[loogie1]

Thinking these may fit. will strip my valve to measure o-ring size, when i get near a garage.
https://www.ebay.co.uk/itm/M3-3mm-A2-ST ... SweChcrf~5

[Sanchez]

Thinking these may fit. will strip my valve to measure o-ring size, when i get near a garage.
https://www.ebay.co.uk/itm/M3-3mm-A2-ST ... SweChcrf~5

Iirc 45mm length required for bolts.

30mm large oring and the 2 smaller 17.9mm required.

[martauto]

Conclusion: If your valve diaphragm is damaged, an acceptable (and almost no cost solution) is to remove the entire top of the assembly and replace it with a flat plate and gasket/O ring.

So in the long run Brian, what are the negatives with this fix ?
I have thought about doing this but held back .

Mart.

[Brianmoooore]

The only negative is a very small amount of heat added to the air coming from the ventilation system, even when set to full cold. You can easily check the results before committing yourself by pulling out the inline fuse to the heater valve or unplugging it.

[martauto]

OK, so please dont shoot me down for this one.
I do have another valve to replace the one already in the car which I was told was OK but dont really know.
For the want of NOT doing this twice (in my sixties and a big lad ) I am thinking of doing the "mod" now and know I would have heat for the first time in my car ?

This would save sooooo much time and effort for sooooo many people /maybe ?

Mart.

[BenHar]

I am thinking of doing the "mod" now and know I would have heat for the first time in my car ?

Mart.

A leaking diaphragm shouldn't stop the heater from heating.

What are the symptoms of your problem?

Ben