Heater matrix

[adster]

How easy is it to remove the heater matrix?
I've got a feeling it's blocked up with 23 years of grunge, ive got some coolant system flush stuff to try but don't hold Out much luck with it.

[Andy_J]

The heater is the Elan is not one of it's more impressive features, so there could be no gunge in your matrix. However if you do want to remove the matrix you will need to take the dashboard out. It may be easier to flush the matrix via the pipes in the engine bay

[epipete]

Really not a job for the faint hearted, it's not difficult as such but it is complicated and time consuming and is an overkill for the flush that you are planning. The matrix is also quite high in the system so unlikely to clog up.

Why do you think the matrix is gunged up? Lack of heat? If so then the first thing to check is the supply to and from the matrix, as Andy says this is via two (metal) pipes that protrude through the bulkhead, behind the plenum the metal only protrudes a couple of inches and are then connected to rubber pipes which can be traced foreword in to the engine bay and one of which is connected to a valve. The valve is operated by the heater control on the dashboard.

Running the car with the heating on should result in both of these pipes being too hot to touch, if you start with a cold car with the heating off and run the engine til the pipe prior to the valve heats up the pipes beyond the valve (to the matrix) should, I think, stay cold, turn the heater on and the valve should operate and allow the hot water through (and return). If this doesn't happen the your problem is with this valve rather than the matrix.

Pete

[baldyash]

Have you changed the heater water valve in the engine bay. It is a common fault which causes the heater to run cool/cold. I have had to do mine for the very same reason, & its a cheap & very easy fix. Volvo part used---see wiki I believe. I can show you if you want as I'm only down the road!

[adster]

There's is no heat from the heater but the pipe with the valve in does get hot but the pipe coming out stays cold.
So my thinking was that the matrix was blocked and not allowing water to circulate?
I guess I could attach a pipe to each end of the matrix and attempted to flush it to see if water flows through it?
Could it be an air lock?

[Brit-Car-Nut]

Like baldyash said, the valve is always suspect as is the vacuum control hoses and controller.
Just click on the picture to see a larger version.

heat.jpg

[adster]

The valve does move when I operate the control, or does this not matter?
I could try and bypass the valve and see if that has ant effect?

[GeoffSmith]

Externally, mine appeared to move but after it blew itself apart it was obvious that it was not doing a lot other than impeding the flow of hot water into the heater:



http://wikilec.9600.org/index.php/Heater_valve

[epipete]

All indications suggest the valve is the issue, it appears to be closed hence the lack of hot water past it. This could be caused by 3 things:

1. Failure of the valve
2. Failure of the heater control knob
3. Blockage somewhere beyond the valve, ie the matrix.

It seems to me that you're going to lose your water in finding out so therefore drain it down, remove the valve and inspect it, whilst drained down you can connect a hose pipe to the heater matrix pipes and flush some water through, from this you will have eliminated 1 & 3 above.

This will then suggest an issue with the heater control knob, this, as per John C picture above, is a part of the vacuum system the intricacies and secrets of which we can save for the time being

Does everyone else agree with the above as the way foreword.

Pete

[dapinky]

Pete, I mainly agree, but with reference to your far-more recent waterworks maintainance, you possibly know best....

...the only thing I would say, is to aquire a short (3") length of hollow pipe (copper plumbing pipe will do for now) before removing the valve. If it is done on a fully-cold engine, you may get away without loosing too much coolant by sticking a finger up the pipe after you remove the valve....

...just replace the valve with the hollow pipe and clamp it up a bit to stop leaks....

now, the heater should have water flowing permanently, so it will tell you if the valve was working or not (even if it appeared to move, externally - although it may be completely obvious if it's as bad as some have been).

If all is well, then the valve is probably at fault, but with the possibility that it could still be the vacuum system not being powerful enough to move the lever fully (split hose) or not working at all (duff part somewhere else in the system?).

Next test could well be to fabricate a sort of 'U' shape out of your left-over copper pipe bits (does everyone else keep 'useless' 5 or 6 inch lengths of offcut pipe, or is it just me???? My wife says I'm odd!) - then you can basically join the 2 hoses which pass through the bulkhead and into the heater - thus basically taking the heater out of the equation (if you've drained the syatem fully, then there's really no advantage in re-sealing it as suggested - but it helps if you wish to retain as much of your antifreeze as possible, or if you expect to need to run the car (back into a garage etc) whilst investigating the problem further.

You can now stuff a hosepipe into the heater 'exit' pipe (the one nearest the right-side of the car - without the heater valve) and back-flush the matrix to clear any rubbish.

[GeoffSmith]

If all is well, then the valve is probably at fault, but with the possibility that it could still be the vacuum system not being powerful enough to move the lever fully (split hose) or not working at all (duff part somewhere else in the system?).

Good plan (mine ran for a long time with a piece of copper pipe kindly provided by the AA) and of course once the valve is removed, you should be able to see if it is working or not.

[epipete]

Yep Dave, I agree completely and thought about the pipe to replace the valve and, yes, I have a stock of copper piping in the garage to match the gold deposits in Threadneedle Street

[Rice crispy]

I think i have a plastic valve in the garage somewhere that i got on a group buy that you could have for what i paid for it or replace when you can get one. Happy to meet up to hand over if it suits

David

[adster]

thanks David, i'll keep it in mind..i've got to drop it at the garage tomorrow afternoon for the cam belt and water pump to be done. So i'll check the valve out at the weekend.

[Rice crispy]

No problem working from home tomorrow so if I get a chance will have a rummage. Maybe meeting in Dunmow tomorrow night for a pint with Melvyn (lotusnut) so if you fancy a drink let me know and I could bring it just in case
David

[adster]

well it seems that after driving it for a few weeks now that the heater does give out some heat, only some though!
so im guessing that is normal?

But now im getting used to the car i'm realising how rubbish the brakes are, so thats the next step!

[Rice crispy]

Mine gives plenty of heat well enough for the top to be down even this time of the year

[epipete]

Mine gives plenty of heat well enough for the top to be down even this time of the year

[mikeydude]

Mine is definitely blocked up and I have a new one to fit but never got round to it.
I tried to clear it by blowing down the hose etc and it was completely blocked....I got a bit to blow out but that's about it.

So, they definitely do block up

[epipete]

well it seems that after driving it for a few weeks now that the heater does give out some heat, only some though!
so im guessing that is normal?

But now im getting used to the car i'm realising how rubbish the brakes are, so thats the next step!

Well, in this weather, my priority would be sorting the heating (including some seat heaters) after all you can spend a fortune on brakes but it'll make no odds if you find a patch of ice!