# Heater matrix fun



## John-H (Jul 13, 2005)

Anyone fitted a GSF heater matrix in a Mk1? I just reserved one at £41 (they gave me a 30% tempter on top of a 60% Black Friday discount!)?

Anyone done this job? Wondering if I can take the dash in and out in a weekend. Obviously I'll have to gas down the aircon before.

Just wondering if there are any shortcuts?

Was hoping mine was coupler o-rings but alas not 

viewtopic.php?f=2&t=1603138&p=8312674


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## NickG (Aug 15, 2013)

Well I've taken one out before and can confirm it isn't a fun job, most of the track folk resort to smashing it out!

These are the fixing locations that might help you...




























Hope that helps!


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## 3TT3 (Aug 30, 2014)

Mine gurgles a bit.
By the looks of things as long as it doesnt start belching, itll be fine


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## auspicious_character (Sep 4, 2016)

I've done a mk4 golf one before and i found there was enough wiggle room without degassing the ac.

Worst case scenario the box clips into two pieces


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## Allspeed (Oct 7, 2016)

How many miles do you have up John-H


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## John-H (Jul 13, 2005)

Allspeed said:


> How many miles do you have up John-H


162k now. My S3 was up to near 300k and I'd replaced the o-rings after suffering similar symptoms - which was a complete cure. The TT has a genuine matrix leak [smiley=bigcry.gif]


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## John-H (Jul 13, 2005)

NickG said:


> Well I've taken one out before and can confirm it isn't a fun job, most of the track folk resort to smashing it out!
> 
> These are the fixing locations that might help you...
> 
> ...


Thanks Nick. That may come in useful!


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## John-H (Jul 13, 2005)

auspicious_character said:


> I've done a mk4 golf one before and i found there was enough wiggle room without degassing the ac.
> 
> Worst case scenario the box clips into two pieces


That's very interesting. Can you describe a bit more what you did? How did you slot in the matrix from the top without removing the whole ac unit?


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## auspicious_character (Sep 4, 2016)

I removed the dash bar and there was enough pull space in situ.


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## John-H (Jul 13, 2005)

auspicious_character said:


> I removed the dash bar and there was enough pull space in situ.


Having some spare time finally I've got this far:










In trying to remove the bar I've removed the obvious yellow painted nuts - two at each side, one under each screen pillar and a strut to the front on the right just under the windscreen. The bar is loose but won't come off the studs and seems to be held by more than just the wiring loom. What else did you need to detach to move the bar - I take it it's just a case of a few inches for access? Does the aircon unit need detaching from the bulkhead too? Obviously without degassing I can't move the aircon that much.


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## auspicious_character (Sep 4, 2016)

Find where the bar is caught, could be where the captives are tight in the bracket?
You have to remove the heater box bolts to be able to wiggle the box into the car a little so you can get the inlet and outlet pipes through.
Naturally take the plastic bits off to make them as short as poss.


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## John-H (Jul 13, 2005)

Thanks. I found a section in Bentley on removing the tube which says it can be removed completely if the wiring loom is untied but also shows a bolt behind the windscreen wiper motor through the bulkhead plenum chamber - not sure about that?

When you say plastic bits removed - you mean the straight o-ringed hose couplers like these?










My heater matrix comes with moulded one piece plastic pipe connections sealed to the matrix that don't come off (the couplers clip on these) as in this picture:


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## auspicious_character (Sep 4, 2016)

Yeah, those things.
Have to be changed on a diesel conversion.

Is there a strap or anything in the area of the wiper motor?


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## John-H (Jul 13, 2005)

I really can't see anything. I'm wondering if it's a left hand drive thing as the Bentley manual is USA based. I'm just removing clips from the loom and steering column but things are wrapped around both sides of the bar.


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## John-H (Jul 13, 2005)

There was indeed a long bolt through from behind the wiper motor - dead in line with the steering column and under the top strap so it was hidden from view. I can pull it forward a bit now.


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## John-H (Jul 13, 2005)

I couldn't easily get to the AC end nuts and I didn't want to risk bending the pipes and causing a leak so luckily the EVAC unit is in two halves and can be split by removing the clips.










Finally I could pull back the heater half of the EVAC unit to expose the top of the matrix:










And back enough to get the pipes over the insulation.










You can see the thick condensed goo inside - about the consistency of neat cordial - that needs cleaning out.










The schedule has not been helped by GSF selling me the wrong matrix ... hmmmm ...


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## auspicious_character (Sep 4, 2016)

Now is your chance to get a decent matrix!
Google mk4 golf and see what's said about the cheap ones.

Compare the weights in your hand too, this isn't a job you ever want to do again.


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## John-H (Jul 13, 2005)

It certainly isn't. Luckily TPS had the correct one in stock which is in now but I'm struggling getting the two halves of the EVAC back together. I might have to loosen the AC end after all. It came apart Ok with a pull but the studs pressed on the bulkhead are stopping it aligning.

With the heater end studs in place through the holes, but loose, I can't get the lips of both halves to align. One problem being the weight of the loom and bar but I have them suspended on string at least.


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## John-H (Jul 13, 2005)

I loosened the nuts at the AC end but kept them on the end of the studs. After more faffing and heaving and with the lower nut of the heater section loose on the end of the inserted stud (the bulkhead hole is slotted here allowing movement) I eventually managed to get the lips to engage facing me and quickly got one of the clips on,.










Then the second front one, the top...










..the underneath one and finally the two at the back.

All the nuts on the bulkhead are now tight and all the heatshield bent and screwed back into place. I'll get the rest back on in the morning. That was a very awkward job.

Thankfully I noticed the difference with the heater matrices before fitting. You can see it more obviously here end on.








(original Audi part on right)

The fixing screw holes are the same as are the coupler end fittings but the angle, origin and length of the pipes and the angle of the bulkhead flange seal are all different. I recon if I'd fitted it I wouldn't have been able to get the couplers on.

The correct Audi part number is 1J2 819 031B which is the superseded replacement with the original part ending "A". The GSF invoice has the same number quoted but the GSF part has a different number (in the same position moulded on the pipe as the Audi part) but the number "1JD 919 031" looks like an Audi number but seems to be entirely invalid with not even a Google search coming up with anything.

TPS said there were two parts and asked me if mine had air conditioning which it has. I don't know but maybe the GSF part was for a non aircon version?


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## Allspeed (Oct 7, 2016)

Looks a mammoth job John


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## John-H (Jul 13, 2005)

Allspeed said:


> Looks a mammoth job John


Certainly was. The main problem was the lack of any clear instruction. Audi specify complete HVAC removal and cutting brackets. Also AC degass. I'd spoken to various independent suppliers who helpfully confirmed that it was a day's labour as the entire dash needed to come out. So depending in labour rates could be around £500. One confirmed that it wasn't necessary to de-gas the aircon and online comments about similar vehicles confirmed. I was about to give the car to an independent but they couldn't fit me in over my holiday so I thought I'd take a punt myself as I had free time.

It is a big job. Most of it is time consuming disassembly and reassembly with the odd broken captive nut or plastic piece. The main difficulty I had was knowing how much to detach the HVAC unit from the bulkhead. The practical solution is to remove the heater end nuts and loosen the AC end nuts. Then it's possible to split the HVAC unit and reassemble. No need to de-gas. Hopefully this can help others similarly tempted.

As a warning here's the mess you are faced with:


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## John-H (Jul 13, 2005)

Glad to report that it's all working well now and the car is toasty warm again rather than like a dank dripping cellar. The sweet smelling coolant condensate leak had spread to all corners of the ducting which I washed out and the carpet all around the heater had soaked up quite a bit of coolant - so that still needs to be washed out. There's still a lot of damp to remove from all over the car from weeks of driving around in the cold damp weather with no heat so the windows are still misting up at the moment but it's slowly getting clear.

Thanks to auspicious_character for letting me know that a de-gas wasn't necessary and to Nick for the very useful pictures. Those nuts were difficult to find and access with every chance of being dropped into the depths of the heat shield. The aircon end ones were well hidden requiring bending back of the insulation and could only be felt with a finger. A long 10mm socket on a fine ratchet was necessary for those. I should add that the long sticky out thing in the green circle is a drain spout and not a mounting.


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## auspicious_character (Sep 4, 2016)

I will claim a chocolate medal one day.


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## silkman (Jul 29, 2004)

This looks like a mammoth job.

Was quoted from two Audi shops (one authorized and one independent) about 200eur for this. The benefits of living in poor Greece :roll:

Heater matrix part is either 18 for a Hella part or 35 for a Nissens part. OEM is 160eur.

Hella









Nissens









I don't think I should bother myself at those prices.

PS: Forgot to mention that after using an aircon cleaner "bomb" (the spray that you use to clean your aircon ducts) I have had pieces of foam coming from the ducts for one year now. I asked around and they told me NEVER use these aircon cleaners because they disintegrate all the insulating foam in the ducts and electric "doors" inside the heating/aircon module :evil: :x :evil:

Work quoted will also replace all foam in the module


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## SPECSMAN (Oct 11, 2016)

John-H said:


> Allspeed said:
> 
> 
> > Looks a mammoth job John
> ...


I'm trembling just looking at this picture  , it looks like a car in a breakers yard; not one that has potential to go back together.

Very well done.

8)


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## John-H (Jul 13, 2005)

silkman said:


> This looks like a mammoth job.
> 
> Was quoted from two Audi shops (one authorized and one independent) about 200eur for this. The benefits of living in poor Greece :roll:
> 
> ...


I was being quoted a full days labour at least at £70 per hour plus the bits and things could break. Depending where you go of course. I know a cheaper place but they hadn't done the job before so it would be a learning curve for them too and might end up longer than a day.

Amazing that the official workshop manual says a de-gas is required and a bracket needs sawing of and bolting back together. I did none of that.

As it happened I needed the car when slots were available but had some spare time in between so ended I'll doing it but didn't rush myself.

Interesting what you say about the cleaning bombs. I don't think leading coolant adds life to the foam either as some of it seemed a bit fragile. It was all soaked of course and there's only so much you can mop up with kitchen towel.



SPECSMAN said:


> John-H said:
> 
> 
> > Allspeed said:
> ...


Out did look a bit like a car crash :lol:


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## silkman (Jul 29, 2004)

John,

I 100% confirm about the bomb, especially on old cars like ours. A friend of mine with an opel (sorry vauxhall :lol: ) corsa had exactly the same thing happen after a bomb, bits of foam flying over the airducts. Eventually all the foam melts away and the ports don't seal properly... In mine the foam bits that come out, big or small, disintegrate into dust.

This is the type I'm talking about, the one you set in the car and leave the aircon on until the can empties









In the TT, I've had foam coming from the ducts for over a year now, its very annoying. The heater also doesn't work as it used to, I could of try to flush it with reverse flow but since the foams need replacing I'll just pay the bill.

Audi told me its standard procedure to always replace the foam on the module, when you take it out. The hella part has a foam roll with sticky tape for this purpose. Tell me you didn't replace yours... What Bentley says? [smiley=bigcry.gif]


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## silkman (Jul 29, 2004)

Forgot to say that on VCDS, you load up HVAC module and run the test sequence and it should open and close all flaps (you can hear them operate)

Watch the video below from 5:22 how he replaces the foams in the airbox flaps.


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## chisharpe (May 27, 2017)

I would rather pull the engine out or do a gearbox change than this Jesus look at all them wires. Mines approaching 150k I'm gonna pray it keeps working for atleast another 100k!


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## silkman (Jul 29, 2004)

Summer update:
After having this work done in winter (replacing heater core but not aircon evaporator) and also replacing the foams in the heater ports, the TT aircon in 35C+ Greece is freezingly cool :mrgreen:

As I had posted above, the foam insulators in the heater box get eaten away and you have hot air mixing with cold by the ports not sealing properly. Before, despite having new aircon compressor properly filled and checked, my aircon was working just barely. Now its freezing inside the TT.

Also the heater core that was replaced was by no means leaking and in good condition. A mammoth job to replace some 5eur foam tape.

By the way, this is the type of tape that seals the heater box ports. Where I live we call it Armaflex, sold in plumbing supply stores.


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## nicolaitornhoj (Aug 19, 2015)

Just did this. This thread and these helped me quite alot!
It took about 20 hours with me taking my time and Im in no way a mechanic.
Did not discharge the AC.

https://www.ttforum.co.uk/forum/viewtopic.php?f=2&t=150972
https://www.ttforum.co.uk/forum/viewtopic.php?f=2&t=1603138
https://www.ttforum.co.uk/forum/viewtopic.php?t=1135665


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## John-H (Jul 13, 2005)

Well done! It's a gruelling job isn't it!


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## nztt1 (Dec 13, 2017)

silkman said:


> Summer update:
> After having this work done in winter (replacing heater core but not aircon evaporator) and also replacing the foams in the heater ports, the TT aircon in 35C+ Greece is freezingly cool :mrgreen:
> 
> As I had posted above, the foam insulators in the heater box get eaten away and you have hot air mixing with cold by the ports not sealing properly. Before, despite having new aircon compressor properly filled and checked, my aircon was working just barely. Now its freezing inside the TT.
> ...


Does the foam tape go on both sides of the metal flaps?. Im just about to renew mine.


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## silkman (Jul 29, 2004)

nztt1 said:


> Does the foam tape go on both sides of the metal flaps?. Im just about to renew mine.


I think only on one side where the flap meets the opening. You will see traces of the old foam for sure once you get the box out.


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