Heater matrix - is there an easy(er) way?

Discussion in 'Mk2' started by Matt Golf, Oct 12, 2016.

  1. Matt Golf Forum Member

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    Been noticing that coolant dropped off recenty and have discovered that coolant is dripping down the outside of the matrix housing. So thats the problem.

    I dont want this to burst on me. Is there a way of avoiding this before I change the matrix?

    I know the dash has to come off, thats not an issue, even though it takes an age to put it back. Do I have to take the entire air box off? Prefer not to as it means dismantling the air conditioning connection and having to get the thing re-gassed. Can the matrix housing be separated from the air con evaporator housing meaning its accessible without taking the air con section off?

    Finally what matrix should I put on the car as a safe dependable replacement?

    Thanks for help (as ever)
     
  2. mbuk2456 Forum Member

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    I don't know if it's any use to you, but I just did the heater matrix on my mk2 by just removing the lower half of the dash. Don't know how much more complicated ac makes the job but it wasn't too bad considering I had been putting it off for a while. I followed a guide from gti forum which assisted in locating all the fixings rather than assuming I had them all and yanking stuff which was still held in place.

    I went for a hella replacement from gsf. Although they ordered 4 in total before one arrived that was in new condition. The one they had in stock had been trial fitted at some point and the cores were knackered. Others they ordered from central stock looked like they had been bashed about too. Just be wary about ordering online just incase you have the same problem with poor stock.
     
  3. Sam.

    Sam. Forum Member

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    As above, get a decent make such as Hella or Valeo. All are MK3 type now so not prone to bursting.

    I've done them a couple of times now by removing just the lower dash as mbuk2456 said, then removing the whole airbox as one rather than trying to split it inside the car (Although this was non a AC car).

    If you're worried about it bursting you could pull both the hoses off the matrix and join them together with some jubilee clips and a bit of copper pipe.
     
  4. Matt Golf Forum Member

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    Thanks for the replies, I will loop it away from the matrix until I get the time to change the thing. Will try it without dash off first but there is bound to be a clip that is inaccessible unless the dash is off. I seem to remember the AC heat exchanger housing clips to the heater matrix housing so if I can get to the clips I can separate it. I will go for Valeo 812031 which although pricier gives peace of mind.
     
  5. blis Forum Member

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    Matt if yours is an AC model... then it's Dash out afaik and remove the module completely as well. Disconnecting and discharging AC too...

    Once you get the whole module out, then you can clean the AC exchange, clean fans, repair flaps, seals, and freshen up the entire system. It was handy to have the front windscreen out but I think you can do it with it in.

    With windscreen removed I think I had the module in my hands in an hour. It took 11 hours to cleanit and put it all back together.

    20160615_124302.jpg

    Begins on Page three:

    http://framepoet.org/mk2-2016/
     
  6. Ray P Paid Member Paid Member

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    Do something quick mm mine burst over my feet it's not that hard if you know what you are doing.

    Sent from my C6603 using Tapatalk
     
  7. rubjonny

    rubjonny Administrator Staff Member Admin

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    my method, makes this job MUCH easier:
    1. disconnect All 3 nuts in the engine bay, theres another one behind the header tank
    2. disconnect matrix pipes then block the heater matrix outlets to stop it leaking all over the carpets (unless its already blown and leaked everywhere, then dont bother :lol:)
    3. remove the heater knobs and trim, unscrew the heater control panel from dash. remove both under trays + centre console
    4. pull the 4 vents out, then remove the surrounds. 1 or 2 screws and clips per surround plus sometimes some staples
    5. undo the big plastic nut up by the passenger B pillar that holds the fan housing to top of the bulkhead
    6. undo the 2 plastic nuts holding the dash vent distribution box to the main heater box, now the vent surrounds are out the side tubes will give enough wiggle room allowing the front vent housing to come out. leave the side vent tubes in place if possible, can remove them if you need to however (and if you have room to do so!)
    7. undo the screws on the driver side of centre airbox housing holding the plastic trim in place (if fitted), then remove the footwell vent housing. it will come out with wiggling!
    8. finally, pull the entire airbox and fan unit, with heater control cables attached. No fiddling with clips, no faffing :)
    You may need to unscrew the upper windscreen vent assembly from the bulkhead before it will come out, its just above the main airbox assembly and has a screw either side attaching it to the bulkhead

    with the matrix itself, the MK3 and early MK4 units are the same as the MK2 golf one. the late MK4 units are also the same, but to fit them you need a couple quick release couplings from the dealer or robbed from the scrap yard. Make sure you thoroughly clean the matrix if it is brand new, they often come coated with oil to prevent corrosion which gives off plumes of horrible grey smoke as it burns off. you only make this mistake once :lol:

    when you come to refit, make sure you put the side vents in place before you refit the surrounds. if you look closely you'll see that there are plastic tabs that are sandwiched between the dash and the vent surrounds, so they'll never go back in properly if the surrounds are already fitted.

    apart from that make sure you fit the 2 seals to the matrix, there should be a long thin one which is glued all the way round the outside of the matrix to seal it round the edge and a square one to seal the top. if the square one isn't included swap the old one over.

    you may also have to repair the flaps inside the centre distribution box, good sticky back foam should do the job nicely just make sure the glue is VERY strong. you want some kind of foam though as otherwise the flaps rattle about! i found this out the hard way when i used aluminium tape to seal the flaps.
     
    Last edited: Apr 26, 2017
  8. Matt Golf Forum Member

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    Thanks, removal of the entire air box and fan would mean discharge of the a/c system?
     
  9. rubjonny

    rubjonny Administrator Staff Member Admin

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    if it has a/c I would try to split the fan assembly off the blower section same as the 'classic' guide has you do, its in one of the FAQ sections somewhere. you may have to loosen all of the fan housign fixings as well to get enough wiggle room to release the upper and rearmost clips. it might still end up having to be a full dash out job though, and even then you might not be able to get it off and have to split the a/c pipes :(

    follow my tips as above though for all the vents etc as that gives you extra wiggle room and makes the process as painless as possible. back in the day I followed the guide to the letter for my 1.6 driver which involved pulling staples out of the vent pipes to release from the surrounds and such which was a proper nightmare but I did get there in the end. the next time for my GTI I ignored everything the internet said and just did it my way :lol:
     
    Last edited: Oct 14, 2016
  10. Matt Golf Forum Member

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    Thanks, I will see what I can do
     
  11. blis Forum Member

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    Degas and remove dash - No pain, no blood, no worries!

    Jon, it's not worth trying to do this in place as the whole module needs attention and it's a great time to consolidate dash wiring, fusebox, stereo and other wiring in dash.

    Seriously, the effort in removing the dash is less a burden than dealing with this task in place. The driver side vent will be painful a jiggle and there's two screws holding the windscreen vent and the wiggle angles become more complex. Getting it back in would deserve a prize in tenacity. There's also the car stereo and if you've upgraded it's likely the vent support is bent and if I were to do this again I'd modify the dash vent support bracket to make a little room for stereo. When I did mine I have +/- 1mm clearance to back of the head unit.
    20160615_125556 (Large).jpg
    20160617_112724 (Large).jpg

    Then the recirc vent needs some love and if you saw the grunge on the AC evaporator, you'd want to clean it too. It took 45 minutes to remove and 12 hours to clean and repair the flaps with neoprene wadding. Having the whole thing out also highlighted the deformation of the plastics and I used extra neoprene to fill the gaps or the leaks would have been horrible.

    Recirc Vent
    20160617_215841 (Large).jpg

    Gaps in the ducting
    20160617_162946 (Large).jpg

    Clips on the rear
    20160617_233718 (Large).jpg

    Getting it all cleaned up.
    20160617_234049 (Large).jpg

    A chance to clean the AC evaporator.
    20160617_202101 (Large).jpg

    NOTE: There will be balancing weights on the barrel fan and I had to reshim the fan so it wouldn't rub! The spades for the fan motor also slipped so handle with care.
    20160623_134610.jpg
     
  12. shiveraj New Member

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    Brilliant. Many thanks. Just done mine on my '91 8v Gti. I'm sore all over, but taking out the whole unit with cables and fan attached is definitely a good move.
    I left the front vent distribution box, detached from the heater box but otherwise connected, in place during removal. It was then easier to disconnect it from the side vents and remove. I then had room to move when re-installing the repaired heater box and put the distribution box in afterwards (having undone the staples so that the connectors could go in afterwards).

    I lubed all the mechanisms and cables while it was out. Made a difference.

    Thanks again1
     
  13. rubjonny

    rubjonny Administrator Staff Member Admin

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    always a fun jobt he first time round. 2nd time its much easier :lol:
     
  14. Joehough

    Joehough Paid Member Paid Member

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    I've got factory aircon and did it without disturbing aircon, just lower half of dash out, releasing the clips was fiddly but managed it.
     
  15. Rooster

    Rooster Paid Member Paid Member

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    Bit of a thread resurrection

    I’ve done this numerous times before and tend to do it leaving the dashboard in the works for me.

    Today’s drama - the lower bulkhead fixing (centre of heat shield above the manifold). The nut and threaded bolt are rusted together. Tried holding the bolt and turning the nut with limited movement but now I’ve burred the threads. Any suggestions? Everything else is released and I’m on the verge of getting the hacksaw to it
     
  16. PhilRyder

    PhilRyder Paid Member Paid Member

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    Don't use a hacksaw.............angle grinder is the way to go :lol:
     
  17. Tristan Forum Junkie

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    If you wind it out it'll either snap, or wind the studd out of the heater box, leaving the nut on it, on tge engine side. Bit of a fiddley job getting it back in, if you decide to leave it like that.
    I had the exact same thing on one of the last ones I did.
     
  18. Rooster

    Rooster Paid Member Paid Member

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    I used a hacksaw in the end as I was in the verge of setting fire to it
     
  19. Rooster

    Rooster Paid Member Paid Member

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    Now it’s out I think winding the fitting out of the airbox leaving the nut on the engine side would have been the answer.

    Refitting I’m going to try that. Sadly the nearest replacement fitting I have is the one that you use to mount the coolant reservoir. Should do the job but will be a proper faff.
     

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