Water still coming in :(

VAG fool

VAG fool

Member
I have posted this in Pearl's thread but it might get overlooked, so pardon the double post as this is doing my head in!
Rear vents done, no leaks. Dried car out, refitted rear carpet (mistake)
Rear trim panels removed and recent heavy rain has shown a drip from high up on offside D post only, appears to be from OSS, which is an unknown quantity. Water is running down the wiring harness and appears to be the root vause of original puddle in battery box etc.
(headlining needs refurb anyway so I am going to removing all post trim in preparation)
Thoughts & experience of this?
IMG_20210311_192736_6_resize_70.jpg
 
Unfortunately, I have the same problem. I first noticed water in the battery tray, so I assumed it was the well-known issue with the air vents underneath behind the rear bumper. However, I also noticed that the headliner had been discoulered and was soaked after it had rained. Tried to clean out the water conducts of my OSS, but as soon as poured water over the roof, it came straight through. My guess is that the rubbers have aged and have become too stiff, maybe have even cracked somewhere. Given my lack of skills, I decided to cover all the water ducts on the roof with ducttape. It's not the prettiest of solutions, but at least no more water is coming in. I have read somewhere on this forum that there is a solution but it involves taking quite a bit of stuff off on the inside. As my OSS is faulty anyways, I decided that ducttape will do.

In your case, however, since you are redoing the headlining, you should be able to see where the water is coming from. In my case, it seems to be between the C and D pillar on the passenger side.
 
Check that water is coming out of the drain channels at the top of the tailgate door on either side.
If not, the water in the drain channel will back up and spill over its edge and find its way in the space above the roof lining, a sure tell tale sign is discolouration of the head lining around the rear side windows.
Use a length of stiff metal wire to poke inside the drain channels to push any crud that's acumilated over the years.
Once those channels are clear, water will be able to drain away.
 
I did wonder if it was blocked OSS drain channels, found a bit of thin ptfe sheet in the works plastic rack this morning (flexible and slippery) so will draw it along the drains and see what comes out at the ends.
 
VAG fool said:
I did wonder if it was blocked OSS drain channels, found a bit of thin ptfe sheet in the works plastic rack this morning (flexible and slippery) so will draw it along the drains and see what comes out at the ends.
Click to expand...

Not trying to be too negative here, but I did that as well. Still, water was coming in... It won't hurt trying though, and I really hope that cleaning the drains will fix it for you. Fingers crossed :)
 
It's definitely worth a try, if the plastic is long enough, I think it will pop out at the other end where the water comes out when the channel is clear.
 
If it isn't the drainage channels I found that on my car it was the seals that the OSS makes with the frame of the car were completely perished and were actually wicking water into my car. I had very obvious wet patches on the headlining though. The only resolution was to remove the OSS and replace the seals with new ones. I know that @Kleynie is very experienced with repairing OSS. I found that the repair was not super hard however it is not a one person job to lift the roof out as it felt like it weighed something like 60-80 kilos and is huge because everything between the front windscreen and the tail gate comes out as one assembly.

Leak from open sky sunroof rear panel

Hi, I have found this forum a wealth of information so far and not needed to post anything but I can't find any detail about the rear glass panel on the OSS (the pane between the boot lid and the rear opening panel). My 1.4 TDI with OSS is getting pretty wet inside the rear of the car with wet...
www.a2oc.net
 
Kleynie is local to me, I was going to go to him for headlining anyway (no watermarks, just baggy facing fabric) but car will be out of MOT soon so that makes things a little more tricky.
One thing at a time.
 
hydo14 said:
If it isn't the drainage channels I found that on my car it was the seals that the OSS makes with the frame of the car were completely perished and were actually wicking water into my car. I had very obvious wet patches on the headlining though. The only resolution was to remove the OSS and replace the seals with new ones. I know that @Kleynie is very experienced with repairing OSS. I found that the repair was not super hard however it is not a one person job to lift the roof out as it felt like it weighed something like 60-80 kilos and is huge because everything between the front windscreen and the tail gate comes out as one assembly.

Leak from open sky sunroof rear panel

Hi, I have found this forum a wealth of information so far and not needed to post anything but I can't find any detail about the rear glass panel on the OSS (the pane between the boot lid and the rear opening panel). My 1.4 TDI with OSS is getting pretty wet inside the rear of the car with wet...
www.a2oc.net
Click to expand...
Yes, it was only after removing and fitting a replacement OSS on my lads A2 that I found the cause of the water ingress, after putting and fixing the replacement OSS I did a leak test just to make sure everything was ok, I saw the water dripping in at the rear side of the OSS and following the trace of water it pointed to the drain channel on the rear drivers side of the roof. So I got an old motorbike clutch cable and poked it down the drain channel and re tested it with the hosepipe, low and behold, no more water ingress and has been good for over a year now.
 
If the water is coming from where @johnyfartbox says, then you are getting water in the guide channels of the OSS, there should only be grease in those channels and not water. This probably means that the seal between the gutter and the channels is shot. In the below picture you can see the seal running between the gutter and the guide channels, I suspect this is perished at the rear, letting water through. If so, its and easy repair.
I have also re-attached the pictures of the OSS drains.

Photo 28-02-2021, 12 40 08.jpg
Front drains.jpgInternal drain compressed.jpgRears drains compressed.jpgTailgate drain.jpgPhoto 28-02-2021, 12 40 08.jpg
 
Thanks for the pics, really useful. I havent tried to open the OSS yet, given the iffy weather, but might risk opening it with the hand crank to get a good look at the seal.
I have tried the "credit card" trick but cant seem to get anything down into the channel so didnt force it.
 
I have a thin rod that is meant for cable pulling, it’s about 2mm diameter and 1m long. This just about fits in the drain hole from the boot hinges and from the corners of the bonnet upwards. You can also use a long cable tie.
 
I went back to this and may have had a breakthrough. On the nearside, my.bit of plastic easily slotted into the roof drain and I could run it all the way through to the windscreen base. A little mud pushed out at the tailgate end.
On the offside, I really struggled to get the plastic fiddled in, feeling some resistance, then something started to give...
This is what finally came out of the drain channel alongside the fixed panel end.
Clear silicone sealant! The rest of the channel appears to be free of obstructions.
IMG_20210313_174434_1.jpg
 
That looks like the tape Audi use on the original installation. Your rubber seal looks like it’s been pushed in?
 
Its definitely a bead of clear silicone, I see a lot of it on dodgy engine "rebuilds" that have failed.
Unless that is what Audi used originally? It doesn't look very VAG to me.
The white stuff is ptfe sheet.
Now the seal is strange thing, the front 40mm or so on both sides of the fixed panel is not secured to the glass, the rest of the seal is ok.
 
I just remembered that we have an endoscope video camera at work! I'll grab it tomorrow and see if it reveals any more.
 
In that case I suspect your roof has been apart before. VAG used metafoil tape to seal the rear, I thought that’s what I was seeing. If it is silicone then someone has been messing.
Ian
 
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