Passenger footwell and under seat soaked

[robertboeke]

I got my 2003 Z4 a few weeks and have gradually been working through it's "quirks". The latest being that while I was checking the B Pillar airbag control unit (I have an airbag light on and DIS says that's where), I found that under the seat was soaked all the way to front of the footwell. So I've had the seat out today, carpets up etc. and used a wet vac and heaters to get everything as dry as possible.
I think the water probably came in via the bulk head as the the drainage at the bottom of the windscreen and around the blower intake was absolutely filled with leaves, mud etc. this was all cleaned out a week or so ago.
What I'd like to know is whether there is anywhere else I should check for water ingres, I really don't fancy another day drying the carpets! Thanks.

 

[Zedebee]

The carpets and sound deadening material do soak up an enormous amount of water before you notice.

Front bulkhead is a candidate. Water can also accumulate in the cavities behind the rear bulkhead where the roof mechanism is located and slosh forward, which is the same accumulation that drowns the roof motor. More likely is the waterproof membrane behind the door card has failed and water is entering from the bottom of the door.

If on the right hand side (driver’s in UK), make sure the yaw sensor (under carpet) is not soaked as these can fail and are expensive.

 

[SonnyA85]

I have the same issue and it's coming from the passenger side roof drain where the motor used to be located.

Carpet was soaked and had a puddle behind the seat. So I hoovered it up using a wet vac.

Next job is to clean the drain and get rid of the bungs.

 

[Richfarr]

I had the same thing last year soaking wet carpet. The leak came from the door seal, take the door card off (10 minutes) and check out the grey seal is still in place and stuck down. I glued mine with silicone

 

[Mau]

On my first Z4, I had soaked carpets twice, due to a poorly fitted windscreen (first left, than right). Admittedly; not the likeliest compared to the above, but still good to keep in mind if everything else fails.

 

[robertboeke]

Thanks for all the advice
I'm fairly sure the roof drain is clear, poured water and it came out where I'd expect. Same for the windscreen drains now.
Regarding the door membrane. I've pulled the bottom of the door card and can see the bottom of the membrane is definitely in place and sealed. I've also sprayed a load of water against the door/window/wing mirror and then gone around the door from inside checking for any ingres. is this sufficient testing or do I really need to remove the door card?
Anyone got any tips on how to check the windscreen seals/where to look?

 

[Rock lobster]

Can I ask what codes you have been getting with your issue?
I have started getting 987b which is related to the tensioner firing circuit but can’t find any info on what it means?

I wonder if I have the same issue maybe.

 

[robertboeke]

Sure. I have two error codes:
sbsl 983e satellite b pillar control module fault
sbsl 9858 satellite b pillar control module fault
I think these are related to the left hand b-pillar airbag control module, mounted on the inside of the sill underneath the carpet. I'm hoping that replacing and coding the new one to the vehicle will solve the issue. But if anyone knows better then please correct me

Regarding your code, I think it's related to the seat belt tensioner/firing circuit (which I don't know much about, but I think it's to do with the little firing piston that tightens your seatbelt in an accident, this part https://www.ebay.co.uk/itm/301813358011).
Hope that helps.

 

[robertboeke]

Update
I think (hope) I've found all of my leaks. If anyone stumbles across this hopefully this will help:
- There was water ingress from the bulkhead, this was due to the drainage at the bottom of the windscreen and around the blower intake being blocked. Removed windscreen cowl and cleared everything out, checked drainage was free with jugs of water.
- At some point water had been getting behind the seats due to the roof drains being blocked. Cleared these with 2.5mm twin and earth electical cable.
- Water was finding it's way onto the lower door seal, there are two holes front and rear on the door seal, I added one more at the lowest front point of the door seal.
- The door membrane is a common issue but not mine, I removed the door card and the membrane looked good, to be sure I sprayed lots of water at the door window and wing mirror and checked inside for leakage.
- Lastly I've noticed a very small gap where the door window doesn't quite meet the seal, I've adjusted the camber of the window which has improved it slightly but I think the seal may have lost it's "volume/plushness" and need replacing. See red marking on image below for location.

 

[ruffles]

I'm not sure if this applies to your car or not but the sound pipe was the cause of our water leak. https://z4-forum.com/forum/viewtopic.php?t=135385

 

[robertboeke]

Thanks ruffles, I'll take a look at that... I really don't fancy having to try and dry out the footwell again!

If it continues I might embrace it and seal the floor, add some goldfish and stick a perspex screen over the top.

 

[Special Kay]

I remember having a similar problem on my old Z3, water entering the cabin . I used a product called Gummi Pflege on my rubber seals. I was told that over time the seals shrink and lose the elasticity they had to create that water tight seal. Gummi Pflege restores this to some degree. It helped my problem enormously. But you do have to make sure all your rain channels are clear for any of these fixes to work correctly.

 

[enuff_zed]

In addition to Gummi Pfledge, which does restore a fair bit of suppleness and shape to the seals, I also prised the seal away and fitted a few strips of double sided foam tape to push the seal out a little.

 

[Special Kay]

In addition to Gummi Pfledge, which does restore a fair bit of suppleness and shape to the seals, I also prised the seal away and fitted a few strips of double sided foam tape to push the seal out a little.

Thats a fantastic idea, wish i'd thought of that at the time

 

[robertboeke]

I thought my leak was resolved, but I checked after some rain and after washing today and the footwell is damp again.

This evening I removed the footwell speaker and it's cover and pulled the carpet back. I got my wife to spray water along the bottom of the windscreen and along the gap between the front wing and the bonnet.

I found a slow trickle of water from around where the speaker would be. I plan to investigate some more over the weekend, but if anyone has any suggestions I'd be grateful... Getting fed up with leak hunting!

 

[SonnyA85]

Got the same issue now as well.

Both drains cleared but still water making its way to passenger side somehow.

Next jobs are check the door seal and front cowl drainage.

Don't suppose you can use a spray gun with some UV dye mixed with water and then a blacklight from inside the car to see where its coming from?

 

[Special Kay]

Got the same issue now as well.

Both drains cleared but still water making its way to passenger side somehow.

Next jobs are check the door seal and front cowl drainage.

Don't suppose you can use a spray gun with some UV dye mixed with water and then a blacklight from inside the car to see where its coming from?

That's a great idea, as long as the UV dye doesn't leave permanent residue to your soft top, windows or paintwork. Good luck I hope you rectify the issue quickly

 

[SonnyA85]

I thought my leak was resolved, but I checked after some rain and after washing today and the footwell is damp again.

This evening I removed the footwell speaker and it's cover and pulled the carpet back. I got my wife to spray water along the bottom of the windscreen and along the gap between the front wing and the bonnet.

I found a slow trickle of water from around where the speaker would be. I plan to investigate some more over the weekend, but if anyone has any suggestions I'd be grateful... Getting fed up with leak hunting!

You manage to get this sorted?

I dried my car again and it's filled up behind the seat. So it's definitely still getting in somehow.

I power washed my front drains but now thinking I may need to remove them to ensure they are definitely clear.

 

[enuff_zed]

I thought my leak was resolved, but I checked after some rain and after washing today and the footwell is damp again.

This evening I removed the footwell speaker and it's cover and pulled the carpet back. I got my wife to spray water along the bottom of the windscreen and along the gap between the front wing and the bonnet.

I found a slow trickle of water from around where the speaker would be. I plan to investigate some more over the weekend, but if anyone has any suggestions I'd be grateful... Getting fed up with leak hunting!

You manage to get this sorted?

I dried my car again and it's filled up behind the seat. So it's definitely still getting in somehow.

I power washed my front drains but now thinking I may need to remove them to ensure they are definitely clear.

Have you checked the door membranes yet? They're the favourite place for water to get in if they've been hacked about.

 

[robertboeke]

I thought my leak was resolved, but I checked after some rain and after washing today and the footwell is damp again.

This evening I removed the footwell speaker and it's cover and pulled the carpet back. I got my wife to spray water along the bottom of the windscreen and along the gap between the front wing and the bonnet.

I found a slow trickle of water from around where the speaker would be. I plan to investigate some more over the weekend, but if anyone has any suggestions I'd be grateful... Getting fed up with leak hunting!

You manage to get this sorted?

I dried my car again and it's filled up behind the seat. So it's definitely still getting in somehow.

I power washed my front drains but now thinking I may need to remove them to ensure they are definitely clear.

I think so. As others have said, check double and check again the door membranes. I thought mine were ok but the seal along the bottom was only loosely stuck,a few minutes after spraying with water it would start leaking through.

I also found that a rubber bung was missing near where the wing and door meet, this has also led to the back of the speaker corroding a bit.

Good luck!