Mr Self Destruct

With the bad weather we've been having recently, I noticed that my Golf has two heat settings; cold, and bloody freezing! Now in the early nineties VW recalled all mk2 Golfs due to an exploding heater matrix problem, due to a design flaw they couldn't handle the pressure the cooling system runs at. However, rather than replace the matrices they fitted a bypass valve. These valves are now showing their age and tend to seize up, blocking the flow of hot coolant to the heater. Problem is you can't buy them any more, so if the bypass valve goes a bollock you need to replace it with the standard hose, and unless you fancy risking scalded legs, replace the heater matrix with one from the mk3 Golf.

So, having traced the problem to my bypass valve, I went to GSF last week and bought a new matrix and the hoses. By the way you can't buy mk2 matrices any more, so no worries about getting the wrong part!
GSF do two, a cheap arsed one for £21+vat, or the OEM spec one for £37.80+vat. I went with their reccommendation for the OEM one as apparently its more heat-efficient than the aftermarket jobbie.

So on with the job:

While the engine's cooling down, unscrew the gear knob and pull off the gaiter:


Unscrew and remove the driver and passenger side undertrays (lots more screws than shown in these pics, but you'll find them):



Undo the screw by the gearstick, and slide centre colsole back to remove, and remove the connection for the cigarette lighter:


Undo the screws and remove the side panel:


Unscrew the centre heater vents at the top as shown, and lift up the tabs at the bottom to remove:



Unscrew the dash mounting bolts at the side and underneath. This allows the dash panel to be pulled forward at the bottom to improve access for the air distributor box.




Unscrew the two nuts arrowed and pull out the air distributor box. It needs a bloody good tug and some serious wiggling to get it free:



At last, the heater!


Unscrew the three bottom box mounting screws. Two on the right:

One on the left:

Pulling it down and forwards to remove:


Now we have three cables exposed, held in by clips which need prying off with a small pair of pliers.
Blue does hot/cold, black ones do face/screen/feet:



Fuck up number 1. It wasn't until I tried to get the heater box out that I realised there were three cables, not two.


Next is the plastic duct from the blower. Take off the insulation cover, held in with four screws to access the duct. This duct joins to the heater box with a square housing, with 6 clips (fuck up number 2: I was told there were 5 clips holding it on. I discovered the 6th when it broke off pulling the heater box out!), 2 each side, 1 on top and 1 on the bottom:


Grrr...


Look at the vent coming out the top of the heater box to feed the windscreen. Its held in place by two screws (one either side, though I couldn't get the camera in to get the other one) which, if undone will allow the duct to flex and ease removal of the heater box (this is best viewed through the dash air vent hole):

Mr Self Destruct

Moving outside into the engine bay now, when the engine is fully cool pop the bottom radiator hose off and drain all the coolant out.
Then take the water hoses off the heater matrix and remove them along with the bypass valve and t-piece.


Undo the two nuts holding the heater box to the bulkhead:



Along with the nut holding the blower duct to the bulkhead too. This is to provide some movement of the blower duct to help get the heater box in and out:


Now comes the moment of truth! Back inside the car grab hold of the heater box and pull it back, down and out, wriggling it as you do. I found it an absolute bastard of a job but it came eventually. Mind you, that was probably because I left a clip in and a cable attached as mentioned earlier.
GOT IT!!!


Push the clips at the side outwards slightly and pull the old matrix out, put the proper rubber seals/gaskets round the new one (fuck up number 3: do this in the warm! I did it outside in sub-zero temperatures, and the rubber round the top of the matrix wouldn't stretch enough to fit, and ripped, hence the duct tape round the edge holding it on), and slot it in place:


When trying to fit the heater back, I found it simply would not go! The reason was that the bracket ringed in red was catching on the windscreen vent. Having a good look at it, I found it has no use at all. Maybe it does on another car, or if air-con is fitted there may be a cable that clips to it. I don't know, but on my gtd its completely redundant. So I chopped it off and the heater box went straight in. Thanks in some part to the loosened blower and screen vent ducts.



Fuck up number 4: When I cut off the redundant bracket I had the heater box the wrong way up. I ended up cutting off the bracket that holds the hot/cold heater cable in place!
Its now araldited to the other cable so I hope to fuck I never have to do this job again!


Re-fit the heater box, lining the windscreen vent duct and the blower vent duct up, wriggle the heater box so that the mounting studs poke through the bulkhead, do up the nuts in the engine bay (including the blower duct nut!), fit the heater pipes, fill up with coolant and fire the engine up !
Attach the blower vent clips, the control cables, tighten up the screen vent mounting screws, then its just a case of re fitting all the ducting and trim, not forgetting to bolt the dash back in place too.

So now I have a driveable car with lots of gorgeous continuous hot air blowing up the windscreen.

Sorted!!

67splitty

A fucker of a job very well explained Mr SD

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BEER, ITS MORE THAN JUST A BREAKFAST DRINK!!!



Garage updated again
71 Karmann Ghia 2275cc 164bhp@5660rpm
10Plate Chevy Spark!!
08 Vauxhall Vivaro (work)125bhp
69 CI Sprint caravan

WS11

I have the same problem, fancy doing mine? Bet it would take you half the time second time round.

Mr Self Destruct

Yeah and make twice the fuck ups!

bodhi

Mine been Knackered in my mk2 for about 3 years, heard it was a bastard of a job so kept leaving it.

Didn't realise a mk3 matrix fitted just squashed the one i was breaking

I'll just carry on driving my bug its slightly warmer and doesn't leak as much water inside

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www.tyreshinckley.com

Meerkator

You are a hero! About to give up after hours trying to do it a la Haynes, googled the problem, saw your answer (brilliant photos!), and from where I was (stuck), box was out in 30 minutes! Back in tomorrow - then I hope to swelter.

One option - instead of disconnecting cables, you can:

- Pull off ventilation, heater and fan knobs
- Take off control trim (fragile clips!)
- Unscrew control plate (2 screws)
- Unplug fan wires from back of control plate

Cables and control plate can then be taken out with the air box.

Beware - mending your heater removes the very clear Black Ice warning!

Happy warm motoring.

Meerkator

Mr Self Destruct

Glad I could help bud, amd those are good tips!

Mr Big

I find it easier that way too.

Jon, you bought ANOTHER mk2?

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Wanted: 3 door Mk2 Golf or 2 door Mk2 Jetta.

Mr Self Destruct

BUSTED!
No mate, I didn't take all the pics here so I robbed some from a how-to guide on a South African website. I'm surprised no-one clocked the air-con unit or the two different carpet colours before now.