Blocked drain holes on a6 c5 2.4 auto avant flooded interior

[JAAUDIA6]

I have a 2004 A6 2.4 Avant which seemed to have blocked drain holes in the engine bay.
I park my car on my drive which as a 30 degree slope facing upward. This morning I found that the rear footwell passenger side had 4" of water in it, on top of the factory fitted mats as well. When I checked the engine bay, the battery compartment was also full of water, I believed that the drain plug is located below the battery, so took the battery out and poked around a bit then whoosh! what seemed like gallons of water disapeared under the car.
My question is:- Is that the only drain hole or are there any by the wings or another one in the engine bay? Will what I have done stop water getting into the cabin? or are there any other drain holes I should be looking for?

[Sam]

There are two drain holes in the plenum chamber, one near the battery and another towards the centre of the car near the brake booster.

[NickPicks]

You also need to lift the front passenger carpet, dry it out and check the central convenience module for water damage.

This is a common A6 C5 problem, which can be expensive to fix if not caught early enough.

[nigelbb]

I had the same problem with my Quattro 2.7T about three months ago but to my regret did not lift the carpets & get all the under felt dried out properly which resulted in a bill of £770 for replacing the Tiptronic gearbox ECU last week. I just mopped up with old newspapers & cloths but clearly while it was dry on top it was still damp underneath. I managed to push the rubber drain plugs out while I was clearing the leaves so hopefully I will not encounter the problem again.

[NickPicks]

The only problem with removing the plugs completely is that you might suck engine fumes into the plenum chamber and into the car through the air conditioning. Whetehr you think this is better or worse than the risk of water ingress is up to you.

[Golf tdi Hal]

Has anybody had any luck poking/clearing the rubber bungs in the drain holes without removing the battery? I am feeling lazy and the weather is crap...

[NickPicks]

It only takes about 30 minutes to do the whole job including removing the battery. Even if you don't have the radio code, you can use a lighter socket battery saver.

I expect you could poke something thin and wiry down the hole, but I don't know whether it'd do as good a job as a crafty finger.

[Sam]

You can do it from beneath the car too but wear a diving mask, snorkel and something with elasticated cuffs.

[big1pie2003]

Just cleaned mine out, one of them things that I started doing when I service the car. Glad I did as the thing was jammed full of leaves etc.

Took me about 30 minutes and I cleaned everything with rag. I only cleaned out the one under the battery tray as I didn't realise there was a second drain hole.

Whereabouts is the convenience module? Is it that box full of electrickery next to the master cylinder and servo?

Pat.

[NickPicks]

No, the CCM is under the carpet just in front of the front passenger seat.

The second drain hole is under the brake servo. You can reach it quite easily.

[big1pie2003]

Thanks, I'll have to have a look at mine. Had no issues (yet) but did get some water in the footwell last year hence the "cleaning out the drain regime".

I'm no car designer but it would be obvious to me to that an electrical box in the footwell is not a good idea.

I've not looked yet but I'm going to try a bit of home made waterproofing, whether thats re-sealing with silicone or placing the whole unit inside a polythene bag and sealing it up. I've had winters in the car when the footwells seem to be constantly wet from snow and rain nevermind the blocked drains.

And prevention is definately better than the cure with the cost of repairs.

[Golf tdi Hal]

Has anyone just drilled a hole in the lowest part of the plenum chamber or any other water-collecting pit? are there any issues with water spray coming in and best way to stop the rust?
I am not about to do a 'Top Gear' and blow a hole with my shotgun..... :-o

[big1pie2003]

I wouldn't drill a hole in any body work.

I might be mistaken but the body work is treated and if you disturb the finish (Think it might be galvanised-zinc coated) you run the risk of rust. Depends how long you want to keep the car I suppose. And also if the panel is aluminium or not.

Also, you would need to check beneath any hole you drill to ensure you dont drill through something real expensive.

How far would you go, a 3mm or a 20mm? What about the structural issues? I believe the MOT rules are (something like) no holes within 30cm of a structural component.

I'm all for DIY fixes but this sounds a bit ropey to me (and I'd try anything once) I just added the cleaning of the drain holes to my service regime. As I service the car summer and winter whether it needs it or not, I've managed to avoid any further drama's with water ingress (once I read about it on here!).

[JAAUDIA6]

Hi Guys,
Cleaned out the plenum chamber, lost the grommet in the process, seemed like gallons of water gushed under the car, BUT! it rained last night and my rear footwell is full of water AGAIN! about 3". As I park on a slope it seems the water has run down from under the front passeneger seat, the front footwell of the passenger side is also damp rather than wet (could be because it's on a slope?. So the question is where is the water coming from? I have checked the door deals both front and rear and they look intact and good, so cannot understasnd where the water ingress is coming from! Any ideas anybody?

[Sam]

Pollen filter seal is probably buggered.

Press down on the housing and listen for squelching.

[digby2994]

I have the same problem in my a6 c6 3.0TDI Quattro. MMI also affected: telephone module needs to be replaced. Carpets will also have to be replaced as the dealer says they cannot be successfully dried out without warping. Initial repair costs will start around £1000, but may cost more if they find more issues. :-(

With so many owners having the same problem, surely this is a design failure?

[JAAUDIA6]

No wonder the German economy is doing so well, it's supplying hundreds of thousands of Audi spare parts!

[digby2994]

Update: just been to see my car - the whole interior has been stripped out (seats, carpets, & half the centre console). The car still has at least two inches of water over the floorpan. Current repair estimate is now £2000. NOT HAPPY. Seems the plenum chamber completely flooded due to blocked drain holes (I park nose-up on a 10 degree gradient), and once that happens, the water starts to leak past most of the grommets and the pollen filter. Audi think it might have been doing this for a few months, but as the water leaks run under the carpet, you don't notice until there's A LOT of water in the car.

My advice: remove at least one of the drain hole grommets to prevent this happening to your car.

[midge6]

Hi Guys,
Cleaned out the plenum chamber, lost the grommet in the process, seemed like gallons of water gushed under the car, BUT! it rained last night and my rear footwell is full of water AGAIN! about 3". As I park on a slope it seems the water has run down from under the front passeneger seat, the front footwell of the passenger side is also damp rather than wet (could be because it's on a slope?. So the question is where is the water coming from? I have checked the door deals both front and rear and they look intact and good, so cannot understasnd where the water ingress is coming from! Any ideas anybody?

I have had issues with water under the passenger side carpet, fortunately it has never caused any electronic modules problems. I can narrow my problems down to 3 options. The first is the two drain holes getting blocked with leaves etc. This is easily remedied and once you know about it, you'll know to check it regularly, especially in the autumn months. The second option is the Pollen filter enclosure seal combined with a build up of leaves (Or whatever) in the channel adjacent to the wing. Again, this is easily remedied, i took the filter housing out, removed the old seal dried off the mating surfaces and applied a dose of silicone sealant - that is a permanent seal and won't leak again. The third option is the rear screen wash tube join at high level in the passenger footwall. You'll notice a fairly strong smell of screen wash (If you use it) in the cab, which is an obvious clue. Again the remedy is simple, reconnect the tube and come up with some mechanical means by which the joint can't come apart.
In all 3 scenarios, i have been amazed at how much water can be soaked up by the carpet sponge underlay (Several litres is no problem) and how long it takes to get the water out and dry the carpet. Depending on the time of year, it can take a hell of a long time to dry out. The only way that i found that worked was to lift the front and back carpets as high as possible thereby encouraging the water to drain out in to floor pan - old towels or newspapers can be left there to absorb this. The front carpet can be lifted so the carpet is practically sitting on the front seat, but the rear carpet needs wedging up off the floor (I used wood). Obviously, you're just opening up the space for the air to circulate and to allow access for packing the towels in.
In your case JAAUDIA6, i suspect that you may have fixed the original problem, but because there is so much water and you park on a slope, it's probably just collecting at the back? I know it's a pain but i would pull the carpets up and give them a chance to dry.
Good luck
Midge

[micheal balbrig]

I have had issues with water under the passenger side carpet, fortunately it has never caused any electronic modules problems. I can narrow my problems down to 3 options. The first is the two drain holes getting blocked with leaves etc. This is easily remedied and once you know about it, you'll know to check it regularly, especially in the autumn months. The second option is the Pollen filter enclosure seal combined with a build up of leaves (Or whatever) in the channel adjacent to the wing. Again, this is easily remedied, i took the filter housing out, removed the old seal dried off the mating surfaces and applied a dose of silicone sealant - that is a permanent seal and won't leak again. The third option is the rear screen wash tube join at high level in the passenger footwall. You'll notice a fairly strong smell of screen wash (If you use it) in the cab, which is an obvious clue. Again the remedy is simple, reconnect the tube and come up with some mechanical means by which the joint can't come apart.
In all 3 scenarios, i have been amazed at how much water can be soaked up by the carpet sponge underlay (Several litres is no problem) and how long it takes to get the water out and dry the carpet. Depending on the time of year, it can take a hell of a long time to dry out. The only way that i found that worked was to lift the front and back carpets as high as possible thereby encouraging the water to drain out in to floor pan - old towels or newspapers can be left there to absorb this. The front carpet can be lifted so the carpet is practically sitting on the front seat, but the rear carpet needs wedging up off the floor (I used wood). Obviously, you're just opening up the space for the air to circulate and to allow access for packing the towels in.
In your case JAAUDIA6, i suspect that you may have fixed the original problem, but because there is so much water and you park on a slope, it's probably just collecting at the back? I know it's a pain but i would pull the carpets up and give them a chance to dry.
Good luck
Midge

The air conditioning drain can also choke causing spillage to passenger footwell.
The drain exit is covered by the sound deadening material on bulkhead.

[Michael Maurice]

I had this last week on my 1.9Tdi, getting the battery out is a pain because its very tight and you have to move the wiring loom out of the way to lift it out. I didn't know about the second drain hole. Its a very poor design.

[mike ryan]

I noticed from day one in my a4 that the windows were constantly misting up. I looked and noticed that the battery tray was starting to fill up so got it all out to clear it. I recommend that you take all of the components ie wiper mechanism battery and any thing else out and clean well as they all hide a whole load of debris. This will migrate and block the holes again.

I managed to clear the second hole which was a fiddle as it seemed to be right underneath the servo. I would also say to lift the bonnet and try to blast with a pressure washer being careful of electronic components of course. This will blow alot of debris out of the scuttle and stop it from causing further blockages.

With regard to drying the carpets why not try a dehumidfier in the car or even a small heater over night. If done with the carpets in place there should be no loss of shape. although i have taken many carpets out of cars over the years for washing and never once has one lost shape so may be that audi are trying to earn a few more quid. Dealers are nothing more than part replacement people. They dont want to try and repair or fix issues as it is quicker and easier to swap for new.

Hope this helps some one out.

[Sam]

This issue is well known yet it's still happening almost weekly just on here alone.

It's really starting to get up my nose now.

How can we (as a whole) make it more obvious to the masses to try and prevent this?

[mike ryan]

I guess that people are only aware of the problem once it has happened so wont go looking for until its to late. A bit of tpm on peoples cars would not go a miss but people dont look under there bonnet from one year to the next. It is only made worse by the entire tray being covered with that black plastic so you would never know its full of water until its to late.

[Michael Maurice]

The fact is that its an awful design flaw, my wife's Volvo had a similar problem but all that happened was the windows misted up. Also the drain holes are very poorly situated. It should not be necessary to remove parts in order to access a drain hole. That is beyond what most drivers/owners can or should do.

Audi should be repairing this FOC

A possible way round it would be to fit moisture sensors under the carpet which sounded an alarm when the problem starts to arise.

[JimTraining]

Better still a simple bilge pump with float switch under the battery compartment......I reckon its a dragons den special! http://www.force4.co.uk/832/Rule-360-Bilge-Pump-with-float-switch--6-Gallons-Min.html?referrer=froogle&utm_source=google&utm_medium=froogle&utm_campaign=pid832 Just need the bulkhead fitting out of the side and hang your red ensign off the aerial. I reckon I have a couple of pumps kicking about somewhere from a 40 year old boat I had that leaks less. Or perhaps lead flashing and a victorian style down spout. Sorry, tired of damp carpet and didn't fancy forcing the pollen filter out either!

[crugbun]

Mine is a 2001 A6 estate.
I now have a permanent leak into the passenger footwell that I only noticed when the central locking went haywire.
I rescued the convenience module and left it on the AGA to dry out properly, and added some electrical contact cleaner... that seems to be okay now thank goodness.
Bulkhead drain bungs are clear, and it is obvious that rainwater gets into the air intake for the interior fan blower.
Once the two plastic trims across the bulkhead are removed you can see the two narrow little gutters that run across the bottom of the windscreen. Pour water on the screen and it overflows the gutter just where there is a little plastic clip on the lower one - it runs straight over the gutter and into the fan plenum draining through the pollen filter.
I've cleaned out these two gutters and moved the clip and it has improved, but still overflows into the top of the plenum if there is a lot of water.

Weird problem really, since it has been ok for 10 years! So can't just be bad design.

Is there supposed to be a cover over the pollen filter that has been removed by some forgetful mechanic?

[mike ryan]

Mine is a 2001 A6 estate.
I now have a permanent leak into the passenger footwell that I only noticed when the central locking went haywire.
I rescued the convenience module and left it on the AGA to dry out properly, and added some electrical contact cleaner... that seems to be okay now thank goodness.
Bulkhead drain bungs are clear, and it is obvious that rainwater gets into the air intake for the interior fan blower.
Once the two plastic trims across the bulkhead are removed you can see the two narrow little gutters that run across the bottom of the windscreen. Pour water on the screen and it overflows the gutter just where there is a little plastic clip on the lower one - it runs straight over the gutter and into the fan plenum draining through the pollen filter.
I've cleaned out these two gutters and moved the clip and it has improved, but still overflows into the top of the plenum if there is a lot of water.

Weird problem really, since it has been ok for 10 years! So can't just be bad design.

Is there supposed to be a cover over the pollen filter that has been removed by some forgetful mechanic?


I know on the a4 there is a cover that holds the pollen filter in and also acts as a gutter channeling the water to one side. I cant say for sure with the A6 but i will try to have a look on mine later.

Just as a thought i know that there are what you might call hidden gutters that run along the car and down the edge of the front screen. These may be blopcked causing excess water to run down into the front scuttle area. I always get the pressure washer and blast them out and you would be suprised just how much rubbish comes out.

[Michael Maurice]

I have an A6 Avant 54 plate,

Well, the problem has come back, (see post 21) the front footwell is absolutely soaking.

When i checked the drain holes the one under the battery seemed clear, I couldn't get to the one under the brake servo,

I'm wondering if there are other drain holes that are blocked up.

Can I remove the Convenience module and run the car without it until the problem is sorted?

[WesleyP]

I'm another who has had the same problem. Get a new pollen filter housing, they are only £20 or so. The seal will have perished due to a build up of dead leaves.

[mrnice.]

This issue is well known yet it's still happening almost weekly just on here alone.

It's really starting to get up my nose now.

How can we (as a whole) make it more obvious to the masses to try and prevent this?

To start with you could make it a sticky on the top of this sub forum, on the Land Rover forum Im a member of they have done similiar, and theres also a sub forum that covers all the common faults and also a "busters how to" that gives you step by step instructions complete with pics to help you fix these faults. stops people (especially newbies) asking the same questions over and over again.

If when members work on fixes on their cars they could spend the time to write up a small thread about it (ideally complete with pictures) we could put them all together and build up a comprehensive online library of all the common (and maybe not so common) faults and fixes for members who have yet to experience these faults. It could save a lot of people a lot of time, money and hassle.

Im a firm believer in preventative maintenence , for example this thread has made me aware of the gutters blocking and the pollen filter housing defect something I may not have been aware of until I had a soggy footwell and all the problems that come with it. something I will now be making sure I stay on top of.

Hope this helps.

[blackie781]

I have an A6 Avant 54 plate,

Well, the problem has come back, (see post 21) the front footwell is absolutely soaking.

When i checked the drain holes the one under the battery seemed clear, I couldn't get to the one under the brake servo,

I'm wondering if there are other drain holes that are blocked up.

Can I remove the Convenience module and run the car without it until the problem is sorted?

I had the same problem on my 53 plate Passat, I did run it for a very short time without the ccm plugged in. It wont do the car any harm, its just bloody annoying, one loses the use of alot of things that are taken for granted ie. electric windows, central locking and key fob, remote boot release, im not sure but i think the fuel filler flap is on that circuit too (please correct if wrong). I'm sure there are afew other things in there too. I suppose it depends how much you use the things, disconnect and see how you get on.

I did take my interior out and let it dry in a heated hangar overnight and it all went back in a dream, however I would advise changing the pollen filter seal (as mentioned in another post) it isn't too hard a job and will pay dividends in the short and long term.

1702817029

Hope it helps

Chaddy

[mrnice]

I've just resolved soggy carpet/boot issues on my 167k 2001 a6 1.9tdi avant with that i bought last month.
There was a small amount of water sloshing around in the front and rear n/s footwells, on boot floor, inside tailgate and in cubby hole in boot under toolkit.
Sorry not many pics but I'll describe what I did.
Thought some preventative medicine was in order also so I just tackled all the known problem areas as I plan to keep this car long term.

It was definitely leaking from the pollen filter housing (both from the base and from water dripping onto the filter directly off windscreen due to badly fitted plastic cowl thingy at bottom of screen),
also the tube to rear wash/wipe was leaking from all 3 usual places where there are joins plus it had invented a new few new places to split and leak (inside c pillar and out of wiper motor housing in tailgate). There was a previous fix in the bung between tailgate and roof on o/s- a piece of heavy rubber tube in lace of the plastic tube where it had split due to opening/closing tailgate.

Tackling the wash/wipe I first rebuilt the wiper motor with the kit from audi-
http://i22.photobucket.com/albums/b340/mrnice23/IMG_2280.jpg
This replaces the tube within the wiper spindle that leads to the washer jet and the jet itself, my old one had disintegrated and the jet had disappeared.

Then I traced the tube all the way from the rear wiper to the front bulkhead- It was leaking in the n/s c pillar, in the boot cubby hole (above toolkit), in the rear footwell and at the front bulkhead, I super-glued the bits where it was leaking from joins and where it had split I cut the pipe and used 8 inch lengths of hose to join it again.
I noted that someone had previously ripped (literally) a section of carpet from the n/s rear footwell and jammed an ill-fitting piece of copper pipe in the tube where it had previously split. This rubbish fix was leaking profusely. They had also covered the bare floor there with several filthy, worn, dog-hair-matted bits of old tesco value floormatt.
Rather than bother taking the entire carpet out to gain access to the front footwell I just cut it under where the matt sits since I didn't have a full carpet anyhow. I left this section drying next to the boiler in the house for a week as it was soaking.
I also drilled a new 15mm drain hole just in front of the front passenger seat with a new rubber plug that can be removed if there's a leak in future.
Also, before starting all this I treated the screen wash bottle to some sterilising fluid (miltons), as I didn't fancy legionnaires disease or getting sprayed with any other minging bacteria.
Pic of front n/s footwell with the expensive CCM (comfort control module or convenience control unit or whatever) housing that doesn't want to get wet-
http://i22.photobucket.com/albums/b340/mrnice23/IMG_2282.jpg
I unplugged this and checked it out- it wasn't wet but some wiring had been replaced (and poss the ccm itself) in the past so it had been submerged in water before.

All that took care of the leaking from the screen wash, now for the awkward, annoying bits under the bonnet (water plenum chamber under windscreen).
Removed battery, battery tray, ecu housing, cabin filter housing, windscreen cowl (bit thats meant to clip onto bottom of screen- mine was loose).
Cleaned out both drain holes bellow (someone had previously cut down the bungs), and everywhere else under battery tray.
I got some quality heavy duty external builders silicon and-
Re-sealed ecu housing to bulkhead with the original gasket (I've heard this can leak into o/s front footwell).
Re-sealed cabin filter housing to bulkhead (with a very thick bead of sealant).
Made sure the cowl on bottom of windscreen was properly located (with a smear of the sealant), it snapped into place with a bit of jiggling.
I had previously made a cover for the cabin filter that would stop water dripping onto it so just re-fitted that, not sure it'd be needed but thought i may as well keep it as it doesn't effect the operation of heating/ blower etc.
Ghetto cabin filter cover made from old plastic box-
http://i22.photobucket.com/albums/b340/mrnice23/IMG_2323.jpg

Job done then, it's all a bit ghetto but so far very effective and I look forward to not doing any of it again for many years.

[mrnice.]

good concise post with pics, very usefull. Thankyou.

[mrnice]

Thanks!, seems to have been covered lot but thought i'd add my bit

Cool username btw!

[mrnice.]

LOL thanks buddy, when I went to register my normal username (mrnice on 3 other forums-same avatar) it was already taken, I looked for any posts by mrnice and when I couldnt find any I assumed the name was registered but nobody was using it so I took the name with a full stop at the end and started posting, 30 posts later and you appeared, I must admit it confused me at 1st lol! hopefully if we have different avatars it shouldnt cause too much confusion (doesnt help we both registered in May 2012) but if it does we can always flip a coin for it and one of us could be misternice.

What can I say, great minds think alike!

Take care mrnice from the other mrnice. :D.

[mrnice]

Must add an avatar when i get a minute!, back on the topic though and despite the recent deluge of rain and copious use of screen wash to tackle the greasy Glasgow film of crap on the windows, the floor of the avant is bone dry, happy days! (now to move onto all the other niggly broken bits)...

[djt1954]

Hi, I think you may have the answer to my problem, I went through the usual problem of the blocked battery drain, only discovered when a deluge of water poured over the wife's feet... cleaned that out and then discovered a soaking wet n/s floor. I tried drying this out but then my real problems started when the central locking locked me out of the car. I was only able to open the drivers door with the key and the rest of the doors remain firmly locked. The key fob now does nothing so I suspect I have a waterlogged control unit under the carpet. My first problem is getting to it, do you have any idea how to disengage the central locking to allow me to get at the unit?

[nigelbb]

The only problem with removing the plugs completely is that you might suck engine fumes into the plenum chamber and into the car through the air conditioning. Whetehr you think this is better or worse than the risk of water ingress is up to you.
What engine fumes? Possibly a slight smell of warm oil but that's all. Your engine should not be producing any fumes tht could be sucked nto the cabin unless there is a leak in the exhaust or similar.

[NickPicks]

What engine fumes? Possibly a slight smell of warm oil but that's all. Your engine should not be producing any fumes tht could be sucked nto the cabin unless there is a leak in the exhaust or similar.
Or if the cam chain tensioner gaskets leak and dribble oil onto the exhaust manifolds.

tapatalk by stealth.

[Dr Imran T]

Well chaps, I've suffered the same fate with a lot of problems i.e flooded CCM couldn't wouldn't work etc.

I'm currently trying to trace a leak. When I pour water on the sunroof and it trickles down over the front windscreen/scuttle etc I find water enters the cabin from a channel/vent in the passenger side front sill area. I have highlighted this in the picture.

http://i64.tinypic.com/1zn9baq.jpg

Does anyone know which drain may be blocked for water to enter in this way?

[Sam]

If you've checked that the plenum bungs are clear, it'll be the pollen filter housing gasket.

[Dr Imran T]

If you've checked that the plenum bungs are clear, it'll be the pollen filter housing gasket.

Thanks Sam - I'm sure I had them done by my mechanic. I did read up that the pollen filter housing lets water in, but not sure where the water shows up in the cabin hence my picture :)

The circled area in that picture is where water is coming out.

[Sam]

I'm sorry, I'm not sure what you're asking.

If it's "Is the circled area a potential inlet?" Possibly, but water always finds the lowest point, it could have originated anywhere and just found the easiest path.

With the car off, open the bonnet, remove the plenum cover (if present) and remove the pollen filter. Put your hand into the opening and feel the sides of the plastic channel to see if it's wet. You can also gently push down on the filter housing to compress the seal, quite often you'll either hear it squelching or you'll see water beading on the plastic in the joint.

While you're there you could also check the plenum chamber to see if your mechanic has cleared the bungs. It'll be obvious if he hasn't.

[micheal balbrig]

Would it be an idea to pour the water in the scuttle area again as another test to confirm that this is the entry area.
Reason would be to eliminate possibility of problem with sunroof drain,,although most problems are in plenum / scuttle /pollen filter area

[Dr Imran T]

Chaps, apologies for my ambiguous post. Right to clarify, I did pour water on the sunroof and it came down the front windscreen and over the scuttle panel. I could see what coming in on top of the actual pollen filter when I looked underneath.
When I checked inside the car, water was exiting from the area circled in that picture and pooling at the lowest point underneath the CCU.

I would hazard a guess that the water that enters the cabin filter comes out where I have circled in the picture - it's just a bizarre place to come out that's all. I had the car over to chris on here and he removed the bungs in the plenum..

I will get to the bottom of the matter and fix it properly. Very annoying though.

thanks gents.

[Dr Imran T]

Would it be an idea to pour the water in the scuttle area again as another test to confirm that this is the entry area.
Reason would be to eliminate possibility of problem with sunroof drain,,although most problems are in plenum / scuttle /pollen filter area

Michael - good idea. Will try that in the morning :)

[Scott K]

The sunroof drain runs down the A pillar. Looks like you might have a blocked sunroof drain hose or they have sprung a leak at a join further up. Good luck.

[Sam]

Sunroof drain nipples (fnar) are in the door shut at the base of the A pillar, squeeze the nipples to release the water. If no water comes out, voila, there's your issue. An old bicycle brake cable makes a cheap and easy tool to push in from the sunroof end if they're blocked.

If water does come out, pollen filter gasket would be the next thing to change - There's a guide on here for a Passat which I can find if you want, but it's very easy if you wanted to DIY.