Very wet driver footwell, any common suspects?

[My Dime Is Up]

This issue is well documented. The sunroof is made by Webasto and is used in similar VAG models, such as Skoda, SEAT, etc, so you will find similar threads.

Now it could be the sunroof drains are blocked or are dripping at the exit drain, but in nine times out of ten it's the actual sunroof cassette. I've repaired mine at least half a dozen times, but the repair is temporary. Because the sunroof cassette uses a mix of plastic and metal parts - Webasto used a mastic sealant to sandwich the whole thing together, it's fundamentally a manufacturing design flaw. If they had used a single plastic tray insert such as Volvo for example, we wouldn't have this issue.

The sunroof rubber seal on the glass and bodywork is not designed to be completely watertight. The excess water that seeps through is meant to collect and exit on one of the four drain channels front and rear, however what happens is water pools and eventually finds a way through the mastic area that sandwiches the composite roof.

If you think about it - the car experiences vibration, and extremes of hot and cold every day, basically the ingredients to create a failed bond. The only correct fix is to replace the entire cassette, and because Webasto probably never changed the design, then in another 3-4 years I'll guarantee that will fail too.

What you're seeing is the water dripping from a failed section on the cassette where the seal has opened, onto the roof lining, then eventually down the A pillar plastic trim where it will drip onto the carpet and soak the sound-deadening material underneath.

As a short-term solution, pull the rubber floor mat (assuming you have one fitted) and get paper towelling or a wet vacuum to take up any moisture. Once it's try, get plastic sheeting down until you can investigate properly.

I have been chasing the same fault and have been for the last 3 years. I'm not prepared to pay Audi the best part of £2.5k to replace.

Fixes I have tried included glass-fibre matting, well that didn't work, so I moved onto marine sealants with limited success of anywhere from 4-6 months with no leaks. If you are using a sealant, use tin-foil on top - to separate from the headliner otherwise if you need to investigate again you will be a in world of misery trying to pull apart. Sikaflex make most of the commercial sealants for automotive and marine use including 291i but I'm going to try 591 next or 3M 5200 Marine Sealant.

As we approach winter, it's important to get it fixed, as any trapped moisture will freeze and you'll notice water and condensation on the inside of the windscreen.

Work in a clean well-let environment, or on a decent day when you know the weather will be dry. This is not a job at the end of the day in fading light. The interior grab handle is the worst part, but with the right tool is straight-forward. The interior if light coloured will mark very easily, hence wear nitrile gloves and change them often. You can ease the rubber door rubbers over the roof lining with a bit of persuasion.

Gotocha. The leak I'm referring to is in the second video. Seems to be related to the wind deflector https://www.audizine.com/forum/show...d-footwell?p=14820297&viewfull=1#post14820297

So the best course of action is to drop the headliner, take Sikaflex and apply it around the metal bracket for the wind deflector, overlapping/pressing into the gaps of the existing black sealant?

 

[spartacus 68]

You can try applying the sealant above, but will take a good 24 hours to cure in the right ambient temperature and needs to be bone dry with the sunroof left open. It's not so much the wind deflector, as that still needs to be able to move and open and close as the sunroof is activated. The water simply finds the path of least resistance. If you drop the headliner you can attack from both sides, which hopefully gives you 4-5 months before you need to tackle again.

If you're looking at the whole system - it's worth cleaning and re-greasing the rails as you may hear already hear a little creaking when it's used. Not cheap either at £40 for 90g! OEM part: G00045002.

 

[My Dime Is Up]

You can try applying the sealant above, but will take a good 24 hours to cure in the right ambient temperature and needs to be bone dry with the sunroof left open. It's not so much the wind deflector, as that still needs to be able to move and open and close as the sunroof is activated. The water simply finds the path of least resistance. If you drop the headliner you can attack from both sides, which hopefully gives you 4-5 months before you need to tackle again.

If you're looking at the whole system - it's worth cleaning and re-greasing the rails as you may hear already hear a little creaking when it's used. Not cheap either at £40 for 90g! OEM part: G00045002.

I bought the car rebuilt from a front-end deer collision 2 years ago. When I opened the sun roof it was DIRTY, and I mean DIRTY! I cleaned it out with alcohol and regreased everything. I regrease it when every time winter and spring starts. Its always moved a little slow when its about to move down and close, not sure why. Our good friend from Audizine, Smac770, is recommending I apply sealant between the rails and the sunroof frame but not too much as to inhibit the sliding.

 

[spartacus 68]

If anything breaks on the sunroof, its likely to be the cast alloy cog on the drive motor. Audi will only sell you the motor - but worth taking a punt on the replacement cog from EBay. I assume the motors just wear and tear, as will be carbon brushes I'd have thought, etc. Nothing wrong with applying a bead of sealant, although needs to be light. Study the sunroof where it moves on the rails and there's a little distance - so not likely to foul, it's the last section where the wind deflector compresses as it closes that needs to be clean.

 

[My Dime Is Up]

If anything breaks on the sunroof, its likely to be the cast alloy cog on the drive motor. Audi will only sell you the motor - but worth taking a punt on the replacement cog from EBay. I assume the motors just wear and tear, as will be carbon brushes I'd have thought, etc. Nothing wrong with applying a bead of sealant, although needs to be light. Study the sunroof where it moves on the rails and there's a little distance - so not likely to foul, it's the last section where the wind deflector compresses as it closes that needs to be clean.

Heh will the sunroof closing is the least of my worries. I barely even use it. I can't believe that all USA models come with sunroofs without an option not to equip it. If I were buying a brand new Audi, I'd be sure not to equip sunroofs. Maybe a panoramic roof w/ a sunshade but nothing that the glass moves.

 

[spartacus 68]

If I were buying a brand new Audi, I'd be sure not to equip sunroofs. Maybe a panoramic roof w/ a sunshade but nothing that the glass moves.

It's an attractive extra on the car as it lightens the interior, but the reality is it's going to start causing issues, the very day the new car warranty lapses. Hope you get it sorted.

 

[jdp1962]

It's an attractive extra on the car as it lightens the interior, but the reality is it's going to start causing issues, the very day the new car warranty lapses. Hope you get it sorted.

A few months ago, when choosing my current car (a 2018 SQ5) I had a choice between two; both were 2018 models, both similarly priced but one was much lower mileage, had a higher spec and a much nicer colour (Daytona Grey metallic rather than Brilliant Black non-metallic). I bought the higher mileage one in solid black simply because the other one had a sunroof, and I did not want that headache.

@My Dime Is Up , welcome to our forum; I hope you get it fixed.

 

[My Dime Is Up]

Good choice jdp. Across the pond you guys get it better I guess. in the USA Audi and BMW are marketed as purely luxury cars. We don't get the A1 or BMW 1 series, nor can you option any of the cars Audi and BMW sell with cloth seats or manual seat adjustment. Same deal with sunroofs, they all come with one whether you like it or not.

I'm crossing posting this from Audizine:

I was talking to my grandfather about this job and he brought up a good point that I completely glossed over: why is this much water getting in the sunroof in the first place? I understand the sunroof isn't supposed to be sealed 100% (which to me doesn't make sense. I'd think that the drain tubes should be there just be a backup?) but how is there so much water getting into my sunroof that it is puddling over 20ml of water inside my car? Is it normal that the sunroof doesn't seal this much? If it isn't normal, then I'm looking at two problems: the sunroof isn't sealing enough and the sealant for the wind deflector bracket is breaking down and not sealing well.