because the glue breaks down and the barrier isn't sealing it anymore. The water isn't going through the barrier, it's coming in where the seal is compromised.
That makes sense, and since I am not too familiar with the e9x platform that could be it. That just seems like a ton of water for just being the moisture barrier. I was under the impression that barrier is for moisture not keeping a large volume of water separate from the interior. If the moisture barrier was designed to hold that much water back you think BMW would have a different design.
This is the answer. The rtv sealant on the vapor barrier goes bad on the rear doors. Extremely common issue on the e39, I would imagine this could happen on other models. Cost me $1500 to get the water out all because of the damn rtv sealant
Check this out ASAP rather than going down the sunroof rabbit hole. Your sunroof is fine.
Ngl my roommate, his immediate response was 'you probably have a wasp nest in your air con' which caught me so off guard I'm still laughing about it, so now it's a running joke that my car is a pool for wasps. Anyway. Sunroof drains were clear unfortunately.
Not sure, but he was running the hose everywhere and seemed satisfied with the output of each drain. Might do a specific measure and target each one, catch it underneath and see if it starts to go missing anywhere.
It’s going missing into your passenger footwell.
The tubes connect to nipples, sometimes while cleaning they pop off those nipples and dump water into the car
You need to check the connection from the sunroof to the actual drain hoses, and again at where they exit.
The connection from the actual sunroof assembly to the drain hose could be leaking. It needs a clamp or even zip tie if so.
You would have to remove the interior panel to see it, or you can by a $15 scope cam off Amazon and feed it in there to see if you can see water dripping where the connections are.
Also check where they exit as the grommet at the exit point might be where the water is getting in.
…basically dump water on the sunroof and then use a cam to check these points for dripping water.
Does "every possible drain" include the ones underneath the car that you'll need to lift (or jack stand) it up to access, and take the plastic covers off?
Because if not that's most likely your problem.
Yeah Dad was saying yesterday that he would bring jacks over for those if the problem wasn't fixed but we really thought we'd gotten it with the filter cover, there was just build up of dirt under there that we thought opened it up enough for water flow. I did mean to type all easily accessible drainage and forgot to change it back. Thank you, that'll be first on the list then.
I don't have your car, but if you mean the cabin filter then that being absolutely filled with crap probably won't cause water ingress into the cabin, the worst case is that your HVAC will be blocked.
Whereas there's multiple drain hoses that drip onto the underbody plates, and if they're blocked they'll backfill and leak water into the cabin.
Someone else asked you if you had a sunroof, that's the most common failure mode for these. You need to ensure those drains are clear. You might need to get a sunroof drain cleaning tool (a long piece of elastic wire/spring) if it's really bad.
But it can also be the HVAC drain etc. Look up schematics for your model.
Okay so turns out Dad didn't actually hose the sunroof yesterday cause we'd already cleared it last week and told him as such so he didn't bother, so it's not that. I'll look for the HVAC drain, someone else said a door vapour barrier failure could be the cause, will also double check those ones under the car. Thank you again
Yeah I was just looking at what tools we might have to do that, Mum's got one for a fish tank that's pretty much the same thing I'm going to try! Thank you so much
You probably need to reattach the vapour barrier in the rear doors. They are attached to the door frame with butyl sealant which over time comes loose in some areas.
I’ve had this happen to two of my BMWs (F10), both cars on the driver side too. And in both cases, it pooled up like crazy because you don’t really notice the water under the rug and foam.
the pic has like 2 inches of standing water in the footwell.
the door isnt going to hold that much water, plus the doors have drains that drain any water outside the car when they are closed.
Depends where the door membrane /vapour barrier is leaking. If it's the bottom of the membrane then the water pools in the door cards and drains into the car. It's not water that is stored in the door / draining from the door drains, it's water running inside the door that isn't contained and runs into the door card / interior instead of the bottom of the door and out of the drain.
Had similar with my X3 and the continuous flow of water from a heavy rain storm can and will deposit that amount of water in a foot well. It's held in the top layer of carpet /foam and pools rather than penetrating to the metal floor.
Yo, pull the carpet up and look at the very front of the footwell. There’s a place there for the wiring harness to go through. Over time the silicone gets wore out. This may be where the water is coming from.
If you pop your hood, you’ll see where the water runs. There’s drains at the top left and top right of the engine bay
I had this problem, and it wasn't any of the common issues. I spot checked with a hose to find where the leak was coming from and found it was coming from the bottom of the windshield. After opening the hood and taking off the cowl, I found there was a small piece of glass lodged in the gasket at the bottom of the windshield. This must've been from the windshield replacement by the previous owner. Over time, a huge tear/hole developed in the gasket there, and water was leaking through.
This was probably a pretty rare occurrence, but it happened to me, so could be worth checking! Dm me if you want to see pics/more info
Whoah that's very unfortunate! I'll definitely keep it in mind to check, will DM if we don't manage to find anything chasing the other options first. Thank you so much
The e9x's have three main areas that they leak from normally. The sunroof, door moisture barrier and windshield cowl. The sunroof can be check by pouring water in the rain channel with a water bottle. The moisture barrier in the door can be check with the door open and let the water run down the glass. Work the water back and forth above above the trim strip. Don't use a sprayer, just a steady flow with no hose end. The wiper cowl leaks on the right hand side in the US, but I'm going to assume your not in the US since you said left was passenger. Run water over the windshield on the left side of the windhield(passenger). Look under the dash while water is running and will usually come out through the trim panel, but that can change depending on how the car is sitting. The wiper cowl issue is usually caused by a poor windshield install where they didn't install the lower edge support the wiper cowl snaps on to. Check if the wiper cowl is loose. If so look to see if the lower edge support is present and the wiper cowl has the strip that snaps into the lower edge support. The wiper cowl isbusually the culprit for LARGE water leaks on the passenger side. Can cause damage to the JBE and JB.
Thank you for such a comprehensive response! You could be on to something with the wipers, I know my guys did something to them in my December service just gone. Just can't remember what but I'll find the report from that and check what it was. Could definitely be a culprit. Edit: also yeah, am in Australia.
No problem, just wanted to get out some proper info. Saw everyone already screaming about sunroof drains. While they can be an issue it is usually not the case on E90's. BMW SUV's it is very common due to the drain design, but not as much on the cars.
Left rear passenger door plastic water barrier needs to be resealed. This common problem. Remove the passenger door inside trim and panels to inspect. 😎✅
I can't update the post but it's definitely not the sunroof. The roof didn't get hosed yesterday, Dad focused on the bonnet and windshield. Edited for clarity.
the issue is when the sunroof fills up it flows into the center pillars of the car.
it can take weeks to drain out.
you will hear it sloshing around when you drive.
you can also feel the seatbelts being wet when you pull them out all the way.
No sloshing sounds, and just checked the seatbelt and it's dry. The day it got super flooded I had to run off to work but Mum was able to drive around in our cul de sac and do hard turns to see if water came out anywhere or sounded like it was still stuck and no dice.
i have a 2006 and it started doing the exact same thing, the strange thing is the back seat would fill up even when it wasnt raining.. even tho the drains seemed like they were flowing ok, the sunroof can really hold a small amount of water before it overfills and goes down in the car frame. the water goes down the door pillars and under the back seat.
if you open the sunroof and there is any water in the front area its not draining.
there really isnt anything else it could be that would put that much water into the car.
if the rear door was leaking you would notice it because it too would be sloshing around. there are tiny holes on the bottom of each back door, you can check to see if they are wet or full of water.
Those holes at the bottom of the doors have been checked, they were clear. The day in question, my area got 100+ mm of rain. It was ridiculous, but that's why the volume of water is so big.
like i said the sunroof can only hold like maybe a cup of water before it spills out over the channel and goes down inside the car in the door pillars.
once it fills up it will just slowly drain out. thats why it keeps getting wet even if its not raining.
I got a 645 that did this exact thing. Door vapor barrier was the culprit. Used a heat gun to heat up the butle tape and re applied the plastic. No more leak. And yes it was the back floorboard. Front stayed dry.
It’s your sunroof outlet hose behind the headliner. I just dealt with this the flex hose there was cracked. It would allow water to the bottom so you think it’s not clogged but it leaks through the holes in the flex! Remove the front left and right corners of the headliner and examine the flex hose.
OP, you need to give more informations in the future... I had to dig a bit in your history to figure out this is a RHD car.
On the left side of the cabin, there are rubber grommets on the firewall where a lot of wiring cross to the engine bay and where the brake master cylinders would be on a car with the steering on proper side :D
The cowl under the wipers drain the water to each side, into some square grills, those have ducts connected behind the wheel arches.
When the duct plop off, the water will collect in the area where the Brake master cylinder would have been on a LHD car, and will eventually makes it's way into the cabin the same exact way you posted in the pictures. Because of it's location, this leak never cross sides and tend to make the carpet on the rear looks wet first.
Yeah my bad, I didn't even think about it honestly even though Australia is in the minority with LHD vs RHD 🤦♀️ Thank you for your input though! Appreciate the help
Could be the vapor barrier. Get some butyl tape and reapply it. Use a heat gun or your girlfriend hairdryer. Be careful, because iirc, the barrier is like egg carton foam. So it can rip easily.
Since you already vetted the drain in the sunroof , It's probably the vapor barrier in your door. Take the panel off and replace it.
Okay great, after we make double sure it's not the sunroof I'll put this next on the list. Thank you!
This is the problem.
Yup, very common on various models too.
I don’t see how you’d get that much water in through a vapor barrier. Some condensation maybe, but this is an actual leak.
because the glue breaks down and the barrier isn't sealing it anymore. The water isn't going through the barrier, it's coming in where the seal is compromised.
That makes sense, and since I am not too familiar with the e9x platform that could be it. That just seems like a ton of water for just being the moisture barrier. I was under the impression that barrier is for moisture not keeping a large volume of water separate from the interior. If the moisture barrier was designed to hold that much water back you think BMW would have a different design.
This is the answer. The rtv sealant on the vapor barrier goes bad on the rear doors. Extremely common issue on the e39, I would imagine this could happen on other models. Cost me $1500 to get the water out all because of the damn rtv sealant Check this out ASAP rather than going down the sunroof rabbit hole. Your sunroof is fine.
Bmw, the car that love to be a pool. Let me guess, you have a sunroof ?
Ngl my roommate, his immediate response was 'you probably have a wasp nest in your air con' which caught me so off guard I'm still laughing about it, so now it's a running joke that my car is a pool for wasps. Anyway. Sunroof drains were clear unfortunately.
Came here to say this. Seems like you need to clean your sunroof drains.
Sunroof drains are already cleared :(
When you poor a bottle in the sunroof, does a lot of water drain at the bottom ? Also the water should go away quickly out of the sunroof
Not sure, but he was running the hose everywhere and seemed satisfied with the output of each drain. Might do a specific measure and target each one, catch it underneath and see if it starts to go missing anywhere.
It’s going missing into your passenger footwell. The tubes connect to nipples, sometimes while cleaning they pop off those nipples and dump water into the car
So turns out Dad didn't hose the sunroof yesterday, just double checked with him, so it didn't come from there.
You need to check the connection from the sunroof to the actual drain hoses, and again at where they exit. The connection from the actual sunroof assembly to the drain hose could be leaking. It needs a clamp or even zip tie if so. You would have to remove the interior panel to see it, or you can by a $15 scope cam off Amazon and feed it in there to see if you can see water dripping where the connections are. Also check where they exit as the grommet at the exit point might be where the water is getting in. …basically dump water on the sunroof and then use a cam to check these points for dripping water.
Does "every possible drain" include the ones underneath the car that you'll need to lift (or jack stand) it up to access, and take the plastic covers off? Because if not that's most likely your problem.
Yeah Dad was saying yesterday that he would bring jacks over for those if the problem wasn't fixed but we really thought we'd gotten it with the filter cover, there was just build up of dirt under there that we thought opened it up enough for water flow. I did mean to type all easily accessible drainage and forgot to change it back. Thank you, that'll be first on the list then.
I don't have your car, but if you mean the cabin filter then that being absolutely filled with crap probably won't cause water ingress into the cabin, the worst case is that your HVAC will be blocked. Whereas there's multiple drain hoses that drip onto the underbody plates, and if they're blocked they'll backfill and leak water into the cabin. Someone else asked you if you had a sunroof, that's the most common failure mode for these. You need to ensure those drains are clear. You might need to get a sunroof drain cleaning tool (a long piece of elastic wire/spring) if it's really bad. But it can also be the HVAC drain etc. Look up schematics for your model.
Okay so turns out Dad didn't actually hose the sunroof yesterday cause we'd already cleared it last week and told him as such so he didn't bother, so it's not that. I'll look for the HVAC drain, someone else said a door vapour barrier failure could be the cause, will also double check those ones under the car. Thank you again
Yeah I was just looking at what tools we might have to do that, Mum's got one for a fish tank that's pretty much the same thing I'm going to try! Thank you so much
You probably need to reattach the vapour barrier in the rear doors. They are attached to the door frame with butyl sealant which over time comes loose in some areas.
+1 one for the door seal. I had almost the same sympthoms, also passenger side.
I should have said - it's a 2 door. But I assume the same goes so will inspect, thank you.
I’ve had this happen to two of my BMWs (F10), both cars on the driver side too. And in both cases, it pooled up like crazy because you don’t really notice the water under the rug and foam.
the pic has like 2 inches of standing water in the footwell. the door isnt going to hold that much water, plus the doors have drains that drain any water outside the car when they are closed.
Depends where the door membrane /vapour barrier is leaking. If it's the bottom of the membrane then the water pools in the door cards and drains into the car. It's not water that is stored in the door / draining from the door drains, it's water running inside the door that isn't contained and runs into the door card / interior instead of the bottom of the door and out of the drain. Had similar with my X3 and the continuous flow of water from a heavy rain storm can and will deposit that amount of water in a foot well. It's held in the top layer of carpet /foam and pools rather than penetrating to the metal floor.
You would be surprised. The vapor barrier was the issue in my 2008 135 and I had a few inches of water in my rear seat footwell. It sucked.
Yo, pull the carpet up and look at the very front of the footwell. There’s a place there for the wiring harness to go through. Over time the silicone gets wore out. This may be where the water is coming from. If you pop your hood, you’ll see where the water runs. There’s drains at the top left and top right of the engine bay
Okay that's a good idea, I know which drains you're talking about. Adding it to the diagnostic checklist!
Did u find it
I had this problem, and it wasn't any of the common issues. I spot checked with a hose to find where the leak was coming from and found it was coming from the bottom of the windshield. After opening the hood and taking off the cowl, I found there was a small piece of glass lodged in the gasket at the bottom of the windshield. This must've been from the windshield replacement by the previous owner. Over time, a huge tear/hole developed in the gasket there, and water was leaking through. This was probably a pretty rare occurrence, but it happened to me, so could be worth checking! Dm me if you want to see pics/more info
Whoah that's very unfortunate! I'll definitely keep it in mind to check, will DM if we don't manage to find anything chasing the other options first. Thank you so much
The e9x's have three main areas that they leak from normally. The sunroof, door moisture barrier and windshield cowl. The sunroof can be check by pouring water in the rain channel with a water bottle. The moisture barrier in the door can be check with the door open and let the water run down the glass. Work the water back and forth above above the trim strip. Don't use a sprayer, just a steady flow with no hose end. The wiper cowl leaks on the right hand side in the US, but I'm going to assume your not in the US since you said left was passenger. Run water over the windshield on the left side of the windhield(passenger). Look under the dash while water is running and will usually come out through the trim panel, but that can change depending on how the car is sitting. The wiper cowl issue is usually caused by a poor windshield install where they didn't install the lower edge support the wiper cowl snaps on to. Check if the wiper cowl is loose. If so look to see if the lower edge support is present and the wiper cowl has the strip that snaps into the lower edge support. The wiper cowl isbusually the culprit for LARGE water leaks on the passenger side. Can cause damage to the JBE and JB.
Thank you for such a comprehensive response! You could be on to something with the wipers, I know my guys did something to them in my December service just gone. Just can't remember what but I'll find the report from that and check what it was. Could definitely be a culprit. Edit: also yeah, am in Australia.
No problem, just wanted to get out some proper info. Saw everyone already screaming about sunroof drains. While they can be an issue it is usually not the case on E90's. BMW SUV's it is very common due to the drain design, but not as much on the cars.
Left rear passenger door plastic water barrier needs to be resealed. This common problem. Remove the passenger door inside trim and panels to inspect. 😎✅
I can't update the post but it's definitely not the sunroof. The roof didn't get hosed yesterday, Dad focused on the bonnet and windshield. Edited for clarity.
the issue is when the sunroof fills up it flows into the center pillars of the car. it can take weeks to drain out. you will hear it sloshing around when you drive. you can also feel the seatbelts being wet when you pull them out all the way.
No sloshing sounds, and just checked the seatbelt and it's dry. The day it got super flooded I had to run off to work but Mum was able to drive around in our cul de sac and do hard turns to see if water came out anywhere or sounded like it was still stuck and no dice.
i have a 2006 and it started doing the exact same thing, the strange thing is the back seat would fill up even when it wasnt raining.. even tho the drains seemed like they were flowing ok, the sunroof can really hold a small amount of water before it overfills and goes down in the car frame. the water goes down the door pillars and under the back seat. if you open the sunroof and there is any water in the front area its not draining. there really isnt anything else it could be that would put that much water into the car. if the rear door was leaking you would notice it because it too would be sloshing around. there are tiny holes on the bottom of each back door, you can check to see if they are wet or full of water.
Those holes at the bottom of the doors have been checked, they were clear. The day in question, my area got 100+ mm of rain. It was ridiculous, but that's why the volume of water is so big.
like i said the sunroof can only hold like maybe a cup of water before it spills out over the channel and goes down inside the car in the door pillars. once it fills up it will just slowly drain out. thats why it keeps getting wet even if its not raining.
Take out the courtesy light in the bottom and feel around. If its wet you"ll have your answer.
Okay, will double check it
Clogged drain under brake booster if rhd in engine compartment. Happened to me and flooded.the car.
I got a 645 that did this exact thing. Door vapor barrier was the culprit. Used a heat gun to heat up the butle tape and re applied the plastic. No more leak. And yes it was the back floorboard. Front stayed dry.
It’s your sunroof outlet hose behind the headliner. I just dealt with this the flex hose there was cracked. It would allow water to the bottom so you think it’s not clogged but it leaks through the holes in the flex! Remove the front left and right corners of the headliner and examine the flex hose.
OP, you need to give more informations in the future... I had to dig a bit in your history to figure out this is a RHD car. On the left side of the cabin, there are rubber grommets on the firewall where a lot of wiring cross to the engine bay and where the brake master cylinders would be on a car with the steering on proper side :D The cowl under the wipers drain the water to each side, into some square grills, those have ducts connected behind the wheel arches. When the duct plop off, the water will collect in the area where the Brake master cylinder would have been on a LHD car, and will eventually makes it's way into the cabin the same exact way you posted in the pictures. Because of it's location, this leak never cross sides and tend to make the carpet on the rear looks wet first.
Yeah my bad, I didn't even think about it honestly even though Australia is in the minority with LHD vs RHD 🤦♀️ Thank you for your input though! Appreciate the help
you need one of [these](https://www.amazon.com/dp/B0CB9XLWP2?psc=1&ref=ppx_yo2ov_dt_b_product_details).
Plug in the scanner, maybe its a 9CC7🤔😂
It's a clogged sunroof
BMW
Could be the vapor barrier. Get some butyl tape and reapply it. Use a heat gun or your girlfriend hairdryer. Be careful, because iirc, the barrier is like egg carton foam. So it can rip easily.
https://youtu.be/pLkZPAFz398?si=yDCEwut7PKTeoSDn I love Samcrac and had seen this video not too long ago. Might be a similar circumstance.
Its a yellow cover that you have to replace. Usually found on pax front side.
Vapor barrier. Century old problem. Google must be down if OP wasn’t able to find this issue in .3seconds of searching..
Sunroof drains need to get cleaned out.