Heater Matrix question

[Jerry Atric]

Well, sorry if I'm being a pain in the a**e , but answering my own question, more for others benefit really.

So the heater matrix CAN be removed from the car without taking the whole heater unit apart, altho' the matrix has to be sacrificed in the process. However, as its more than likely fu**ed , it really shouldn't be a problem.
I used a small cutting disc to cut the plastic "tails" that the two heater hoses connect onto. Not too easy as it involves lying on your side in the footwell and angling the small cutter up to the pipes. I cut about three quarters of the way through and then employed a thick screwdriver and prised the unreachable area apart. Then the inaccessible clips can be accessed and the rubber hoses withdrawn . The plastic bits left in the hoses can easily be prised out with the aid of some easing oil to speed the process. The old matrix can be withdrawn without any more hassle. I filled mine and sure enough it was leaking from somewhere in the middle of it , this explaining how I was getting water in both footwells as it just depended on which way the car was parked/leaning.

Hope to get the new matrix by Tuesday ......think it may be "interesting" trying to get matrix and attached hoses back into position and even more interesting getting the whole lot back together again!

Thanks to jakeb for the earlier advice !!!

[Jerry Atric]

JEEZ !!!! how did you do this???
quote....I did not attempt to remove the heater hoses where they attach to the matrix while the matrix was in the car. I disconnected the heater hoses under the bonnet and removed the matrix with the hoses attached to it. When installing the new matrix, I first attached the hoses, aligned the clamps properly and cleaned and refitted the insulation. Then I installed the matrix in the car and threaded the hoses back through the firewall.

Been trying for hours to get the bl**dy thing back together and attaching the pipes makes it impossible to get the matrix back in...Tried loosening the screws holding the blower unit but that didn't want to budge at all and what little movement I did get was of no use. Now trying to poke the pipes through from the engine bay, but the shape and curves of the pipe are not helping and neither is the binding of the bulkhead which is about an inch thick where the pipes go through....F'ing nightmare. Anyone want to buy a Scirocco with out a heater! GRRRRR!

[ThomasD]

JEEZ !!!! how did you do this???
quote....I did not attempt to remove the heater hoses where they attach to the matrix while the matrix was in the car. I disconnected the heater hoses under the bonnet and removed the matrix with the hoses attached to it. When installing the new matrix, I first attached the hoses, aligned the clamps properly and cleaned and refitted the insulation. Then I installed the matrix in the car and threaded the hoses back through the firewall.

Been trying for hours to get the bl**dy thing back together and attaching the pipes makes it impossible to get the matrix back in...Tried loosening the screws holding the blower unit but that didn't want to budge at all and what little movement I did get was of no use. Now trying to poke the pipes through from the engine bay, but the shape and curves of the pipe are not helping and neither is the binding of the bulkhead which is about an inch thick where the pipes go through....F'ing nightmare. Anyone want to buy a Scirocco with out a heater! GRRRRR!

Sorry - just saw this. Also sorry you're having a hard time with it. It's been a while since I did the job, but I don't remember the removal or reinstall being that hard. One thing was I replaced the hoses. It's possible the new hoses were more flexible than the really old ones, but it I doubt that makes too much difference. To reinstall, I did put the hoses on the matrix first, started to push the matrix back into the heater box, and at the same time, pushed the hoses through the holes in the firewall. That worked - but the heater box itself needs to be loose enough so you can manipulate things a bit - so I had to disconnect the 4 blower bolts at the top to do it. Below are notes I wrote to at the time - maybe they will help.

Heater Matrix is contained inside and air box / blower assembly.

The matrix fits in the assembly in a horizontal position and there is a door on the passenger (left) side of the car which allows access.

Remove passenger seat (this makes life much easier).

Remove parcel shelves from both sides of the car.

Remove sound panels from both sides of the car.

Remove gear shift knob and gear shift boot.

Remove radio.

Put heater in full hot position (needed to drain coolant).

Remove heater levers and blower dial. Remove heater faceplate.

Remove 4 Philips head screws which hold center console to dash (upper two) and heater controls in place (lower two).

Remove 2 Philips screws from lower console cubby.

Remove single Philips screw from bottom edge of center console (near fader switch).

Remove screws from sides of lower console.

Move top part of center console forward and unplug blower motor wiring.

Remove top portion of center console.

Move lower console forward.

Remove hot air tube on passenger side of car completely.

Disconnecter hot air tube on driver’s side of car (don’t need to remove it).

Remove wire ties connecting wiring harness to heater box (3 of them)

Remove heater matrix cover (push down on 2 clips on top and it pivots down).

Remove rain tray from under the bonnet.

Drain coolant (disconnect two hoses going to water pump. Hose attached to metal pipe was difficult - unbolted metal pipe from block to allow it to move a bit. Most of the coolant came out of this connection.

Put plastic down in car and towels over plastic.

Disconnect upper and lower heater hoses under engine bay.

Disconnect 4 bolts holding blower motor assemble in place from under bonnet.

Lower heater box and twist slightly towards passenger side of car.

Heater matrix can now be extracted. Hoses will pull through firewall. Be careful because matrix will contain coolant still.

After heater matrix is out of car, insulation can be removed (had to wash this), and hose clamps can be removed - note orientation of hose clamps. On top connection, clamp “ears” face up, on lower hose, clamp “ears” face down.

To reinstall, installed hoses on new heater matrix, installed clamps and insulation and then installed matrix in car - started to insert it into the heater box. Got hoses through the firewall, then could complete getting it into the heater box.

Bolt heater box back into place.

Install new cable ties attaching wiring harness to heater box.

Initially added 4 qts of 50/50 G13 coolant and distilled water. By squeezing hoses could get coolant to flow into various places and then added another 2 qts. Started engine. Engine took a far amount of time to heat up - during that time, periodically the coolant temp gauge would got full hot and the red LED would blink. Then eventually it would drop. Oil temps were fine. Eventually the coolant started circulating through the radiator and the fan came on. Oil temp had reach 86C at this time. Shut off and let car cool. Coolant was at “Min” mark, so added approx .2 qts. Total coolant added was about 6 liters - system capacity is 6.5 liters.

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Part Information:

Heater Matrix: 171-819-031E. No longer available from Volkswagen. Ordered Valeo 812034 which turned out to be identical - same markings (except VW logo), made in France as original. Meyle also makes a replacement, but that is made in China.

Heater Matrix hoses: 171-820-371B. Still available from VW

Connecting Pipe (lower heater hose to hose going to cylinder head): 171-121-140D. No longer available from Volkswagen. VW Heritage offers this part (possibly as a VW Classic replacement). Old part was metal, new part is plastic.

Coolant Expansion Tank: 171-121-407F. Still available from VW.

[Jerry Atric]

Hi Tom, many thanks for the expansive reply and your notes on doing the job.

Today things went a lot better altho' have had to accept some minor mods, mainly with the clips that hold the hoses to the heater matrix. The VW blue sprung clip-together sort are a nightmare to get at by the matrix when its in position, hence why I cut the plastic pipes of the old unit to get it to slide out easily. However, once out, " then how do you get it back in ? " was my problem. I gave up with the VW clips and used a pair of correct size jubilee clips.

Slotted the clips over the matrix plastic pipes and then with suitable lubricant, pushed the rubber pipes through from the engine bay. Big problem is lining the hoses up with the matrix pipes and I had to beg help from my wife who pushed the pipes from the engine bay end whilst I F'd about in the passenger footwell trying to manoeuvre the hoses onto the matrix pipes. Definitely 100% easier with two people involved.

Once the hose was partly on the pipe, I slipped the jubilee clip over the hose and then with a final push, the hose slipped into its correct location on the matrix pipe and it only remained to tighten up the jubilee clips.
Once I re-connect the two pipes back into the cars cooling/heating system, I'll re-check the integrity of the the jubilee clips so I'm putting off for now re-attaching all the panels and trim under the dash as it'll be easier to check if there are any leaks at the pipes into the matrix.

Looking back this horrendous job , I reckon it should be possible to remove and replace the heater matrix without disturbing all the centre consoles as the heater matrix "door/cover" is accessible just by removing the under dash panels on the left hand side. However, you do have to cut the matrix plastic pipes to remove the unit, but once that is done, it is possible to get it back together again as I've just described.....

[mark1gls]

Glad you managed to get it back together, I would check the jubilee clips in a couple of days as I find they do need a little tightening once they settle.

[Jerry Atric]

Thanks Mark, I certainly will ....plan to re-commission the heating / cooling system over the week-end and will certainly leave all exposed below the dash to ascertain there are no leaks from the clips......fingers crossed.