Heater Matrix

Hi all my 8v went for its MOT this morning and the Heater Matrix burst whilst in the middle of it, the MOT tester said they are easy to get but i have heard that they are a pig to change can anyone advise. The car is staying in the garage for about a week to get a couple of jobs done was thinking if i got a matrix i would get them to fit it please help cos i need to make a decision Thank you Thank you Thank you in advance.

 

there's an excellent "rubjohnny" "easy way" heater matrix guide somewhere on here worked a treat for me, see below

the easy way:
1. undo all 3 nuts in the bay that hold the centre box and the blower housing to the bulkhead.
2. remove all 4 heater vents (just pull em out) then remove the surrounds by undoing the screw and releasing a clip
3. remove the console and both dash under trays, then undo and remove the vent housing from the front of the airbox where the centre and side vent pipes connect to and take out the side vent tubes as well
4. at the blower end undo the plug, and also look upwards and you'll see liek a big round plastic nut, undo this and remove
5. go back to middle housing, remove the trim from the driver side and also the footwell vent unit from underneath the blower housing. it may take a bit of wiggling but they will come out
6. remove the heater knobs and panel, then undo the 3 screws holding the slider unit to dash
7. finally remove the matrix pipes in the bay and block the holes with corks or somethign to stop fluid going all over your carpets.

now the entire heater/blower/slider assembly comes right out in once piece, no need to fiddle in the footwell with clips holding the 2 halves together or the clips holding the control cables on

now the airbox is out, undo the clips holdign the blower housing to the main unit, carefully so you dont loose them. now look at the state of the 3 direction/heat flaps, the foam is probably all rotten and needs replacing. some kind of neoprene sticky back foam works well, i used aluminium tape as thats all i had to hand. this works too but unfortunatly now the flaps rattle a bit as they have no foam to muffle them.

the matrix just unclips from the top, make sure you fit the new foam gasket between the matrix and housing, and if you bought a decent kit there will also be a strip of foam that sticks all round the outside edge of the matrix to seal it to the inside walls of the housing

edit: oh and there may be a step 8 that no-one mentions, try to unclip/cut/bend/swear at the aftermarket alarm module and loom thats been wrapped all around the blower unit

edit2: oh! and something nearly everyone forgets. clean the new matrix! they are covered in some kind of anti-corrosion coating see, if you dont clean it off you'll end up with loads of horrible smoke filling the car for a few weeks, and a smell that takes ages to go away. learnt that one the hard way

if you can make sure the new matrix is a veleo one, oem supplier to VW and best quality. some of the other ones dont get so hot, like mine

 

Dash out job ("How-to" here)

Then it`s simple a case of draining the coolant and removing the heater box to remove/replace the matrix.

 

Hi Guys Thank you for that information, I think i will get the garage to do it as i dont even have a garage to work in and it looks fairly?????? complicated. Was looking at a matrix on VW heritage they say its for a MK3 (MK2) and apparently they are better might as well upgrade while its being done. Thank You Thank You

 

No need to take the dash out, replacing the matrix is quite simple using the method above.

 

I did mine without removing the dash, and that was on my drive in February! It was tricky, but if you do it yourself you can repair the flaps foam that will have crumbled.
Get some hose clip pliers (I bought the extension ones) if the matrix hoses dont have jubilee clips, and might be worth buying new hoses from VW to future proof it.
Re-fitting the heater control cable is the trickiest bit from what I remember.
Good luck if you do try it.
I'm not the best spanner monkey, just looked on this forum and gave it a go.

Only thing now is one of my vents now whistles lol

 

Easy way around that is to unscrew the heater controls and lift the whole heater assembly and controls out as one - means you don't have to deal with any tricky cables

 

So much easier with the dash, IMO...at least with the ones I've done there was no way the footwell vents were coming out from under the heater box, no matter how much wiggling went on! lol

I guess though, if a garage is doing it you'd want the minimum labour cost, so dash out might be more expensive. Although, if they've never done one before, it would be easier, and less likely that a rough-ar*ed monkey could break something struggling...

As to which matrix you'll get; no-one stocks a "Mk2" one anymore. The Mk3 item is identical physically, but is made stronger to address the bursting issue, so that's what you'll get even if you ask for a Mk2 one.

 

I had to do mine with dash in as I wasn't going to remove the roll cage to fit a heater matrix, mine burst while driving through Worcester town centre, I jumped out as car was full of steam and rusty coolant! Bloke asked, "Is it on fire?" lol

Sam, good tip on the heater control/cables, that was the most awkward part of the job getting the cable back on.

 

I've done 2 with the dash in, but it'll definately be easier with it out (not that hard a job!)

But I've always found the bolts on the bulkhead for the blower are always rusted/rounded off and need cutting off.

 

Thank you so much everyone, i still dont know what to do for the best, it seems like (erm) a tricky job at best but then i suppose it could go pear shaped at the drop of the hat or it could be a piece of cake and i could end up well pleased. Thank you all for the advice i may give it a go Thank you.

 

Forgot to say... Mk2 hoses are not available, but Mk3 ones fit just fine!

 

Just need to clean the threads with a bit of wire wool + oil to get the nuts off without shearing the studs from the HVAC unit?

 

What I find happens most often is that with the engine bay side nuts seized on, you end up unscrewing the whole stud from airbox (it`s screwed into a brass insert). Not too much hassle from a removal point of view, but getting them lined up again on re-fit can be a pig. I've also had one rip the brass insert out of the box...that one didn't go back...

 

What year was the car? On any I've done the studs have M6 on the engine bay side, and a coarse thread on the other side that screws directly into the plastic (I usually put some araldite around them before screwing back in just to be sure). Unfortunately one of mine has a few broken studs and VW have recently dropped them

 

I've done a few of varying vintages. Last one was an Edition One with AC. Mission!

Now you've mentioned it though, I think the one where I didn't replace the stud, was actual directly screwed in rather than having pulled the insert out...

 

Hi everyone thank you all for the advice, i got the car back at end of last week MOT'd and am using it at the mo, the heater matrix has been bypassed but i have bought a new one inc hoses and spacer, the Garage that MOT'd the car have said they will do the work but are maxed out at the moment so i will book it in at the end of this month. This car likes to challenge me and i have already had a couple of issues since getting her back on the road but am working my way through them. Thank you all again.