Another sodding bloody leak!

[Dan Williams]

Hi all, again!

A few weeks ago I had a leak in the car which I thought was the plenum chamber drains. I cleaned these out and thought the issue was thus resolved. This Saturday I refitted the interior parts that I had taken out to dry the car out from the firstt flooding, confident that it was now sorted. It has NOT been leaking at all until this morning when I checked the mat in the passenger footwell only to find it wet again. My heart sank, and I am currently pretty blooming annoyed - why couldn't it at least have done this on Friday so I could have spent the weekend trying to sort it!?

Anyway, I think it may be the pollen filter. The filter itself is dry but removing the filter in sticking a finger inside the foam around the aperture feels wet, so I am guessing this is now the issue. I'm a bit gutted as I was less happy to tackle this job! It sounds horrendous!

I just wondered if anyone knows of a way to fix this without removing the filter housing and all the associated gubbins?

The thing I dont get is that I water tested the car when I did the plenum chamber - no water coming through, and it has rained heavily over the last two weeks whilst I have had the carpet lifted and again no flooding!? Seems odd that I put it all back together again and suddenly its getting wet? The passenger door has been not-shutting properly, do think it it was on the first catch it would let water in?

I dunno!!

Any ideas appreciated

[niall campbell]

keep the pollen filter out and let the foam dry out.

There are metal seams which are sealed with silicone type material and they could be cracked/ dried out over a period of time

If the door is on the first catch, and wind and rain driving in, then it will leak a wee bit.

Is there water in the scuttle at all ?

Was somebody in the passenger seat with wet feet to dampen carpet ? paranoid ?

did you take the car battery out to clear the scuttle bay ?

I usually stick a hose in beside the wing corner pointing downwards at the windscreen, this drives all the dirt, leaves etc towards the draining hole

[Dan Williams]

I don't think it is the door, even if it had been open a bit I can feel the foam stuff inside the pollen filter housing is wet so I'm almost certain it's that. I tested the plenum chamber and it's draining properly, there's no water in there at all.

[niall campbell]

Take the pollen filter out and foam, stick a hose in the scuttle and let it run for a while, then check .

You will need to look at the putty of metal joins leaking and drying out ............. can be a problem, but not common

Have you got coolant loss as in matrix heater leaking or Air Con leak ?

[Dan Williams]

I don't quite understand what you mean by take out the foam? Isn't it part of the seal? If the pollen filter is foams wet doesn't that mean it is leaking? I spoke to a vw garage today and he thought it sounded like it was the pollen filter. If I had a coolant loss how would I know?

[niall campbell]

The foam will retain water, though it shouldn't be much. If you can stick your fingers in where the filters go, should be 2 ? ................... then sometimes you do get the odd leaf and rubbish in there

Is the pollen filter in the footwell or in the scuttle ? I am sure my 2001 A6 had it in the scuttle , but just cant remember.

If your leaking coolant, look at the expansion tank of the radiator. The water leaves the engine after being warmed up and goes into the heater matrix ( its a small radiator behind dash) and the heater fan blows air through it to put heat in the cabin of car.

They leak eventually, but most cars a nightmare to get to it.

You could also check the pressure of your air con at a garage to see if its leaking

[Dan Williams]

OK I think I know what you mean, there's a concertinaed paper-like filter on top and then a bit of foam inside the housing, the foam I was talking about is inside the seal area (like a ring of foam running around the the seal of the housing), that's what's wet, not the foam inside the housing itself. So it feels like its leaking inside the seal and then running down the outside of the tube of air intake itself, onto the footwell and down into the pit of despair below!

I don;t think its leaking coolant but I will check in a mo when I go back to the car. As for the aircon I am not sure, I havent;t really used it much but I'm sure it doesn't blow cold anyway

I am a bit concerned about tackling the pollen filter removal myself as I have read it's a nightmare of a job which is easy to cause issues.....great

The pollen filter is under the scuttle panel

[niall campbell]

If you look at this post here, then the pollen filter is beside the battery ? [* AUDI A 6 *]( INNENRAUMFILTER WECHSELN )( How to Cabin Air Filter replacement. - YouTube (https://www.youtube.com/watch?v=7Md6VO8bqV8) doesn't get much easier than that

Anyway if you look at this video for your age of car ? If you have posted in the correct section ?

I (https://I)1999 Audi A6 Water Leak DIY Tutorial - YouTube (https://www.youtube.com/watch?v=STMCwA96VfI)


Anyway this reply was at the bottom in the comments, it may help to take off the pollen filter box and seal

The FIX is not completed by clearing the drains, water is still draining into the inside air duct. You have to remove the rain deflector that runs just under the windshield. Apply PB Blaster etc. to the upper edge, remove clips and move the deflector down and swing upwards to unlock deflector. Then you can get to the hidden back nut holding the pollen filter box. Remove all three bolts on the filter box and remove it. The rubber gasket that sealed the air duct has disintegrated. I cleaned up the area and used black silicon caulk to seal the box to the car. I did not use caulk around the duct opening. Earlier Audi routed the runoff water toward the fenders. The A6 has a SUPER design flaw running the water to the center over the interior air duct work where gravity takes it into the foot wells.

[Dan Williams]

yeah that's the layout. I did the plenum drains last weekend and they are working fine

[MiniMental]

Change the filter housing. Simple enough job, took me half an hour (on a Passat mind). My seal had completely disintegrated. An entire new housing including all seals and rain channel was £19.65 inc VaT from VWMD. Yours is Audi so may be more but shouldn't be too different? Maybe vw one will fit?

Leak stopped instantly. My plenum never got full as I took drain rubbers out. But still leaked when it rained.

Mini

[Col]

The Passat exactly the same in the plenum area.

What happens is debris behind the pollen filter housing creates a water trap and coupled with the fact the pollen filter housing gasket is a poor design and fails, this causes further water ingress.

I've done a how-to on here of how to resolve it, read all 3 pages as I updated it quite recently with housing seals. I did both the pollen filter housing and the ECU housing. Link below
Passat B5, B5.5 plenum drain cleaning (http://www.vwaudiforum.co.uk/forum/showthread.php/122697-Passat-B5-B5-5-plenum-drain-cleaning)

[WhiteyAR]

The only issue I had when replacing my pollen filter housing was one of the three rusty nuts sheared off the captive bolt. Also snapped the plastic windscreen scuttle as it was so brittle from age. My new pollen filter housing did not come with a new seal, I used silicon and the only reason I replaced the housing was it already was broken. If yours is in good condition you just need to seal around the opening as per bigcol's excellent write up. It was quite easy removing the windscreen wipers and scuttle panel (three clips, both sides and the middle). When mine was leaking it was quite clear during a water test and a trickle of water would run down from behind the glovebox on top of the passenger carpet.

have you checked it's not your washer hose connection burst which is under the carpet to the bottom of the passenger door?

[Col]

Another one to look out for are the inner door panels. The sealant can get a bit tired on them as well.

[Dan Williams]

Thanks whitey, I have checked the water pipe and it's not leaking. I have water tested the area when I cleaned out the plenum drains and there was no ingress of water (took the glove box out to check). The reason I think it's the pollen filter is that it was wet inside the filter chamber, if I pushed the housing down I could see water squeezing out of the rubber foam seal under the housing. I could also feel water around the inside of the housing. I don't think it's the door as the area right next to the door wasn't wet, it was the area underneath where tye pollen filter sits. Finally I can also see that the pollen filter housing is knackered, bits of it are broken and sticking our. The only ting that is niggling me is that it didn't leak over the previous week even though we has rain, but the night that it did leak I had parked in a slope nose down whereas usually I either park across a slope (with the angle running away from the pollen filtration side ) or on the flat.

[Dan Williams]

Thanks Big col, I will check

[Dan Williams]

Thanks to Big Col (who has demoted himself to Col now I see!) and Whitey and all others that helped me here and on my previous thread. I spent Sunday afternoon removing and re-sealing the pollen filter housing and I have to say it wasn't nearly as difficult or as time consuming as I thought it would be. It probably took me 2.5 hours but that was with a lot of tooing and froing to get WiFi (not available in the garage yet!) and double checking things.

I was a bit worried about the windscreen cracking thing, but in the end I found the scuttle panel went on without a fight and with a helping hand on the other end didn't cause any issues.

Had some pretty big rain since doing it and so far there are no leaks, but I've not battened the interior down just yet in case!

Thanks everyone, Big Col I owe you a pint!