Renewing heater diverter flap lining

[dragon green 5]

I'll be attempting exactly this at the weekend, will let you know how it goes.

I saw your pic on Facebook with the dash out,
Good luck with the rest off it, it is worth it

[fla 9]

I bought a new matrix from Mahle, seems quite well made but didnt have the foam gasket that goes on the inlet and outlet tubes.  I assume its ok to reuse the old one, or maybe cut a new one from some neoprene sheet (i've got a fair amount of self-adhesive 6mm sheet)

[daves16v 1]

My old gasket was knackered and is only on the inside. I have a new one which is about 13mm thick. Not expensive from Heritage.

[daves16v 1]

So I attempted to unclip the first one and broke it, see photos, gives you an idea how it unclips. Be very careful, I will be now.

[daves16v 1]

Done it!

You have to work your way around inserting a small flat blade screwdriver as per the photo (don't go mad or you'll break it) and using a bigger flat blade screw driver to separate it at that point then insert a 2p coin or similar (we all have millions of those) to keep the joint open. Work your way around, the coins do fall out and sometimes the gap closes back up but keep going and you'll get there. Try to pull the joint further open as you go around. There is a clip further inboard, see finger pointing photo. Good luck and be gentle.

[fla 9]

well done!  I've managed to separate most of them, its the one on the inside thats stuck and i cant really pull the two sides apart.  What a dumb clip design though!

[daves16v 1]

Yeah that's the one that almost stumped me, I'll be honest it wouldn't matter much if you had to break that clip to separate it, there's plenty of others to hold it together.

[fla 9]

all cleaned up and refelted nicely.  Problem is that the heater matrix doesnt go down fully, its about 2mm proud of the slot.  Tried taking it out and using the old plastic cover at the bottom which looks to be about 1-2mm shorter, but still no luck.  I've pivotted it and moved it around slightly but it still seems to stop without one side sitting properly.  This is a Mahle matrix.  Anyone else had this problem, and if so how did you solve it?

I was thinking of just putting some butyl rope along the top - to be honest i dont think it will make much difference but i'd rather fit it properly if i can.

 

Thanks

Hasan

[fla 9]

 

Edited May 24, 2023 by fla

[fla 9]

i used some damplifier on the directional flap as the holes were large and the felt just didnt feel strong enough.  I had some thick black felt from some years back, but not enough for anything other than the hot/cold diverter and a portion of the black plastic flap. Need to clean up the outside now and replace the remaining flaky foam gaskets

Anyway, interested in any advice regarding the seating of the matrix

[daves16v 1]

Why not leave the end cap off, can't see it doing much unless it's there as a bottom locator?

[fla 9]

Thanks. Yes, tried that, didn't seem to affect anything. I then opened it again leaving the matrix in place and it looks like the top lip of the matrix is marginally too wide by the inlet and outlet pipes. Literally half a mm.  This part then doesn't sit flush on the housing, but i just cant see where its getting stuck. It sticks out by 2-3mm. 

Maybe I'm just making a big deal out of nothing..

[daves16v 1]

I've got the original matrix out of my car if you need to compare dimensions? 

[fla 9]

Many thanks Dave. I just tried my old matrix and it fitted like a glove. So it obviously some.issue with manufacturing tolerances, but I wouldn't have expected this from Mahle tbh. 

This is the gap size on one side.

Which one did you use btw? I was thinking of either leaving as is or getting one from Nissens 

[fendervg 32]

That's weird - there's definitely some tolerance out at the bottom or the side - or the top molding has warped. It will still work though, but you would need to seal the gap to prevent blower air from escaping, but I think I would just return it as nto fit for purpose.  I think the last one I fitted was Valeo or Hella. Was that one listed as a Mk3 Golf version?

Edited May 29, 2023 by fendervg

[fla 9]

Got a new Febi matrix, fits perfectly. Now just trying to cover those awkward profiles in felt to reduce rattles. Also using some fabric tape on the duct joints to reduce squeaking when cold.

Btw, how do you lube up the bowden cables? All of them seem very dry ie friction seems high

[fendervg 32]

For the cables, I'd say you could just try and work some spray PTFE lubricant into them - something like bicycle chain oil. The problem is that you can't get the inner out, although it's ususally just the exposed ends that corrode, and the casing has a non-friction lining. It's once they are clipped on and there are bends in the cable that the force required to move them can increase a lot. If you can get hold of new ones I'd recommend that.

[Wullie 1]

get one of those little water balloons that the kids chuck about and fill it with light grease.  Put the end of the cable into the balloon and secure it tightly with a couple of cable ties and gently squeeze it while moving the cable back and forth.

[fla 9]

Some good ideas, many thanks. Found i had an old 'pen' of jetlube ptfe oil with a very thin tube. Managed to work a fair amount of this into the gap which seems to have improved things.

Next issue is to work out how to move the diverter arm back a few teeth..