Skip to main content
Topic: MK3 Aircon into MK2 anyone got a guide? (Read 569 times) previous topic - next topic

Re: MK3 Aircon into MK2 anyone got a guide?

Reply #15
A bit more progress today...
I was going to morph together the MK2 heater box top with the MK3 base however the clips are the opposite way round...so that won't work!
I still parted the MK3 heater box to fix the flaps It's  a messy job. Unfortunately I've run out of foil to cover the replacement foam so I've now got some on order.
I have also modded the MK3 heater box so that the footwell/screen flap works just like in the MK2 I'll share photos when I've taken them. Luckily VW put a piece of plastic in just the right place for the mod.

Re: MK3 Aircon into MK2 anyone got a guide?

Reply #16
Playtime again.
I have noted that all the flaps work in the opposite way on the MK3 heater to the MK2. Also the way the footwell/screen flap operates means I'm reverting to using the MK2 heater box with the MK3 HVAC module.

Re: MK3 Aircon into MK2 anyone got a guide?

Reply #17
So I got the dash out tonight. It's got to be a good few years since I last did it. That was to fix the heater flaps and re-attach the double-skinned "cardboard" base moulding which routes the warm air to the screen....or not in my case!
I'd forgotten about the screws which hold the side vents in-place what a pita they are - easy if you remove the vent using a flat screwdriver between the vent and the open/shut vent wheel.  Also looks like I forgot to put the screws holding the centre vents all those years ago....half a job!
I'm hoping to swap the heater units over this weekend. The difficult bit will be ensuring I make the hole in the bulkhead for the aircon in the correct place.....measure 5 times cut once!
I'm thinking of making a template out of some  old bendy ali sheet (gas fire back!)  I'll use the MK2 heater bulkhead bolts as the main reference start with a small hole then make it bigger. The clamp and sponge seal for the aircon radiator feed pipes seem to give room for minor adjustments.
I'll share some more pics.

Re: MK3 Aircon into MK2 anyone got a guide?

Reply #18
Thursday night I took the heater box out. Interestingly the heater flap repair I'd done all those years ago had partially come adrift. I had cleaned the flaps then used foil tape to cover them. I then covered the flaps with foam and covered that with another layer of foil tape. I don't think I'd put a sufficient overlap of foil tape over the foam. Thankfully I've used a slightly different method this time.
I made a template out of card to know where to make the cut for the HVAC drain pipe. Unfortunately I think it might need a bit of adjustment. The problem is lining the HVAC up in multiple points but without the ability to see between the bulkhead and the HVAC.

Today I made-up the ali template to make the cut-out for that a/c radiator outlet in the bulkhead. I've bolted it in using the bulkhead heater holes and do further checks tomorrow.

I'm hoping fresh eyes on it tomorrow will mean this major hurdle has been overcome.


Re: MK3 Aircon into MK2 anyone got a guide?

Reply #19
So there is some good and bad news today.

The bad news first....The bulkhead on a MK3 must be a different pressing to a MK2!

I committed to cutting through the bulkhead for the aircon pipes. Managed to get it all lined-up or so I thought and found that the fresh air inlet in the plenum chamber doesn't line up! The HVAC needs to go flush to the bulkhead but the aircon moulding won't let it....Hmm.

Need to give this some thought!

Re: MK3 Aircon into MK2 anyone got a guide?

Reply #20
Progress.....But I need to upload some pics so you can see where I'm at!
So the mobile welder turned-up to sort my frilly inner arches. True to form, removing the plastic arches showed evidence of more rust so that needed chopping out too!
In advance of his arrival I'd made a recess to be welded into the bulkhead but before making a bigger hole in the bulkhead I just needed to check it was a goer!
So on Monday (edit .... DOH Tuesday !!!) the recess was welded in the bulkhead and the heater box all seems to line-up OK. The bulkhead needs a bit of a tidy-up with paint, the grommets putting back in and some seam sealer but happy I've found a solution.

Re: MK3 Aircon into MK2 anyone got a guide?

Reply #21
Good progress, get some photos up!
Mk2 Driver
Mk2 Silver 8v
Corrado G60 Turbo
Mk2 Red 8v
Mk2 Grey 16v
Mk2 BBM ABF
Bora 20vt
Mk2 Green VR6
Mk2 Green ABF
Mk2 BBM 20vt
3.2 TT Roadster
Mk2 Red 16v
225 TT Coup
3.2 TT Coup
Mk4 Anni Derv

Mk2 BBM R32

Re: MK3 Aircon into MK2 anyone got a guide?

Reply #22
More pics added. Can't find my "work of art" metal recess box (edit: now added).
Made one cereal box model and 3 attempts in metal !!

Aircon Album

Lessons learned so far:
The ali template didn't work too well to align everything. Thankfully I only used a template for the condensation outlet.
Using sticky foam so the HVAC fixings made an impression on the bulkhead worked better than the template. (edit - evaporator removed)
++ more to add !

Summary of the bulkhead recess dimensions:
160mm x 120mm x 40mm deep (edit probably better 35mm deep)
If I was doing it again I would have made it "stilton cheese wedged" (edit: for an exact flush  fit on the inside would have required a lot more work due to the irregular contours and) that would have required more skilled metalwork skills. When its finished you shouldn't be able to notice the difference from the engine bay.










Re: MK3 Aircon into MK2 anyone got a guide?

Reply #23
Playtime again.
I've sealed any gaps round the bulkhead recess with seam sealer and given it a coat of paint. I've also given the bulkhead a fettle sticking sound deadening and carpet under felt on the inside.
I've trial fitted the HVAC and that leads me to the conclusion that my recess box should have been 35mm deep max, not 40mm - the bottom threaded bolt for the HVAC box only just protrudes when the reinforcement frame is fitted - i think I'll un-screw it a little from its plastic mounting which will sort it.
I also removed the white slider "mount" on the far left (RHD) side of the HVAC - that stopped me lining-up the unit properly.
On my late BB there is a cross cut-out in the carpet just where the condensation drip tube exits the bulkhead, unfortunately my bulkhead hole is about 5mm too high but I seem to have sorted it with a round file - Just need to get an extension pipe so it drips in the engine bay and not down the under carpet sound-proofing then manipulate a bung round it.!
I've trial fitted the dash and also the aircon undershelf and they seem to fit fine.
I'm hoping to get everything back together this week since the MOT expires on Friday. I'm not sure I'll have the heater blower working but it looks like I'll be able to do that next week with tips from Rubjonny - wiring isn't my forte!

and another thing...wondered what everyone was on about re headlining dropping. Fed various bits through the boot onto the back seat and must have caught the headlining...next minute the last 2 foot of the headlining dropped...Arrrgh another PitA job!

 

Re: MK3 Aircon into MK2 anyone got a guide?

Reply #24
I seem to be missing a few bits...no doubt the list will get longer!
The HVAC drip pipe has an extension that routes in the engine bay is missing. I'll ring the stealers to see how much it is since I need this to complete the HVAC install. It looks a bit more complex than a simple hose. Our local breakers don't seem to have anything as old as a MK3!
The recirculation flap vacuum bottle. Not sure how this connects. There is an ad for one on ebay but the diagram isn't very clear/helpful.
Various sensors yet to be discovered!

Re: MK3 Aircon into MK2 anyone got a guide?

Reply #25
Do you have the solenoid too?
The vacuum bottle needs to have a solenoid that activates the flap.

Wasn't aware of the extension, my drip pipe just protrudes a little farther than the box.
It looks like I need to drill a hole in the bulkhead to allow it to pass through.
Mk2 Driver
Mk2 Silver 8v
Corrado G60 Turbo
Mk2 Red 8v
Mk2 Grey 16v
Mk2 BBM ABF
Bora 20vt
Mk2 Green VR6
Mk2 Green ABF
Mk2 BBM 20vt
3.2 TT Roadster
Mk2 Red 16v
225 TT Coup
3.2 TT Coup
Mk4 Anni Derv

Mk2 BBM R32

Re: MK3 Aircon into MK2 anyone got a guide?

Reply #26
I think I probably need the solenoid too. But then I never bought it as a full set-up and I don't want a "breaker" on the drive.

What you will find when you put the HVAC in is the drip pipe ends in-line with the bulkhead....so needs an extension pipe otherwise the drips will ruin the carpet underlay/soundproofing. I looked on t'Internet and on the VW manuals site it seems to show a pipe that exits along the bulkhead. I was going to temporarily use a bit of hose pipe but it would be good to know the actual diameter of the bulkhead hole so I can correctly align mine and add the proper pipe later. If you know please post.

My tip for getting the drip pipe and HVAC bolts lined-up on the bulkhead would be to remove the evaporator from the HVAC then put sticky sponge sheets on the bulkhead in the area that needs holes. Trial fit the HVAC and the bolts and pipe will make an impression in the sponge - drill the holes and all should line up.....Unless you have a car to take measurements from that is!

You can then use the HVAC bolt holes to line-up the bulkhead recess that needs to be welded in.

Hope that makes sense?

Happy for anyone to chip in with constructive comment!

Re: MK3 Aircon into MK2 anyone got a guide?

Reply #27
Thanks for the tip, I'll have a go when I (eventually!) get around to installing it.

If you look on Facebook, there is a chap called Leo GS Burley, he regularly breaks mk3s and sold me an entire setup.

Mk2 Driver
Mk2 Silver 8v
Corrado G60 Turbo
Mk2 Red 8v
Mk2 Grey 16v
Mk2 BBM ABF
Bora 20vt
Mk2 Green VR6
Mk2 Green ABF
Mk2 BBM 20vt
3.2 TT Roadster
Mk2 Red 16v
225 TT Coup
3.2 TT Coup
Mk4 Anni Derv

Mk2 BBM R32

Re: MK3 Aircon into MK2 anyone got a guide?

Reply #28
Thanks.
 Info from the other site:
1h0820119a is the part number for the condensation drip valve and it is the same for MK3 and MK4. The dealers don't have it in stock.
I'm going to take a look at the scrappy tomorrow because I want to get the interior back together.

Re: MK3 Aircon into MK2 anyone got a guide?

Reply #29
Ohh, I know what you're on about now!

Good shout with that, I'll get one too.
Mk2 Driver
Mk2 Silver 8v
Corrado G60 Turbo
Mk2 Red 8v
Mk2 Grey 16v
Mk2 BBM ABF
Bora 20vt
Mk2 Green VR6
Mk2 Green ABF
Mk2 BBM 20vt
3.2 TT Roadster
Mk2 Red 16v
225 TT Coup
3.2 TT Coup
Mk4 Anni Derv

Mk2 BBM R32