F11 rear door leak

[Gad-Westy]

I noticed when I got in the car this morning it smelt a bit wiffy. Hadn’t been used in a few days and has sat under a blanket of snow. I noticed a puddle of water in the NS footwell and a little trickle coming down the trim from the door joint towards the leading edge.

Looking online, it seems likely to be the adhesive/sealant on the membrane failing but are there also drainage holes on these that can get blocked? Seems a fair bit of water to me.

[d_a_n1979]

Gad-Westy said:

I noticed when I got in the car this morning it smelt a bit wiffy. Hadn’t been used in a few days and has sat under a blanket of snow. I noticed a puddle of water in the NS footwell and a little trickle coming down the trim from the door joint towards the leading edge.

Looking online, it seems likely to be the adhesive/sealant on the membrane failing but are there also drainage holes on these that can get blocked? Seems a fair bit of water to me.

More than likely the failed yellow grommet issue unfortunately; see here:

https://www.pistonheads.com/gassing/topic.asp?h=0&...

Updates 5 forums link here: https://www.forum5.co.uk/topic/283-f10-windscreen-...

The vapour barries can fail; but rarely compared to the likes of the E39s etc

Generally in the F1x range, it's the grommet on the bulkhead

[Gad-Westy]

Cheers. But I can see a trickle coming down from the door itself. Presumably that cannot relate to the front bulkhead or sunroof etc?

[d_a_n1979]

Gad-Westy said:

Cheers. But I can see a trickle coming down from the door itself. Presumably that cannot relate to the front bulkhead or sunroof etc?

They can hold water in the bottom; so worth taking the door card off and seeing if the vapour barrier has come loose; of if the bottom of the door is gunked up etc

But generally it's the grommet; the water traces to the rear of the car/rear footwells and ends up soaking the carpet & foam underneath etc

If it does turn out to be the vapour barrier, get some of this to reseal

W4 Mastic Sealing Strip https://amzn.eu/d/3HmMTAe

Thats what I used on all my E39s and my FiL's F10 530D

Works brilliantly but you need to remove as much as you can of the old stuff first

Edited by d_a_n1979 on Monday 4th December 21:02

[Geffg]

I had the f10 and Mine was the membrane on the rear door. Got some black silicone and resealed and all good.

[Geffg]

Mine was the membrane on the rear door. Got some black silicone and resealed and all good.

[Gad-Westy]

Thanks both. I'm pretty sure it must relate to the membrane. I had a poke around there today when it wasn't peeing it down and it's clear the the water is dribbling down from the joint where the door card meets the door itself. I'm just waiting for some sealant to turn up then I'll get the door card off and hopefully get it sorted.

[Gad-Westy]

I think I might do the yellow grommet and drainage channel clear up anyway over the next month or two. Seems a good plan.

[d_a_n1979]

Gad-Westy said:

I think I might do the yellow grommet and drainage channel clear up anyway over the next month or two. Seems a good plan.

Makes sense as it'd be sods law if it goes

I did it as soon as I got my previous F01

My FiL wasn't as lucky; his really flooded in the rear footwells and took months to dry out fully

[drmotorsport]

The door membrane failng is a common issue on the f10/f11. Reattaching with butyl tape from BMW is the typical fix. There is another common issue with the yellow grommet in the firewall being overwhelmed by crud as the drainage in that location is poor, but that would mean the carpet at the front would be soggy too.

[Gad-Westy]

Thanks all. I tackled this tonight. Sure enough, the sealant on the membrane was no longer sticking in a few places. I resealed it so hopefully that is sorted for now.

I did notice something else though. On the underside of the door there is a large hole (I guess 15mm or so). On the other doors, there holes have grommets in them but not on the rear N/S door. I guess these are effectively one way valves and let water flow out but not in? I can't imagine this has caused much of an issue here but I will get a replacment anyway as I can imagine some scenarios where it's absence is not ideal.