[joe325]

I woke up and found my windshield wipers running with the car turned off after a rain . Also found water puddled in the rear passenger floor. Checked the sunroof drains and they drained normally. What should I check next?
2007 e92
Joe325

[Cal122]

Normally I would say check the vapor barriers on your doors, you can jamb paper towels under your door panels with the doors closed and usually catch that quickly either after rain or when going through a touchless car wash.

But since your wipers were running, it makes me think water might be coming in through your windshield/cowl and possibly shorted something out given all the electronics in that area. There are several moldings that need to be installed in the proper order to properly seal the plastic cowl to the windshield and prevent water from leaking in through the blower motor. I went through this recently where the previous owner had replaced the windshield and they butchered the install and missed some moldings and actually cut the cowl to make their job "fit". I ended up having to replace everything including the windshield, cowl and moldings to fix the mess.

If you push down firmly with a paper towel on your front passenger footwell carpeting, do you have any water there (usually from the foam insulation underneath)? Depending on how the car is parked, water can typically "roll" from the front to the back passenger floor and difficult to notice it's actually coming from the front. That's what happened in my case.

[joe325]

Checked the front passenger floor as suggested, floor was dry but it’s been dry here for a couple of weeks. I sprayed water for a few minutes on the windshield and watched it flow down into the engine compartment. Was surprised to see the buildup of water as it flowed around the cowl vent openings. Definite leak potential. Didn’t see any water in the car. It’s raining this morning so I’ll get a better check on any leaks today.

[Bims328i]

The sunroof deal for these vehicles is kind of problematic. Even if the sunroof drains appear to be working, the trough can become inundated with water.

If in any case the water builds up above the front edge of the water guide it will just spill over.

The rear portions side guide is even more shallow. Maybe an inch if that. So the rear has two narrow channels with this plastic sub assembly that attaches to the rear guide which has the outlet port to connect the rear drain tubes.

If you park your car on an incline it will favor the rear drain section. Decline, it will favor the front section which is deeper.

I had water build up on my rear passenger floorboard over months before I made the connection that it was in fact the sunroof drains.

Something to do with my passenger side as it really needed cleaning.

It could be a number of things but in my case water was spilling over the rear guide and trickling down the middle pillar.

Even after I had them cleaned, if you pour too much water towards to rear section it can spill over onto the headliner.

I dug around through real OEM to see if maybe my car was missing some seals but no.

There are actual gaps you can reach your finger up and over the front and back door into the guide of the drain tray.

Even if they drain if the car has been outside most it's life it is a good idea to clear all four exit ports. They build up a very minute but gradual debris gunk which clogs up proper draining.

I had some issues with drivers vapor barrier (after noticing water drops on the black kick board panel with "BMW" on it after heavy rains)

Then sometimes would get water over the rocker trim panel and onto floorboard.

Later, I left it level one day at work and come out, there are two small puddles on front mats.

Then water began to pool up on rear passenger floorboard. Would sop it up dry then another rain it would get soaked.

The thing is, the carpet is not like most other cars. No, this carpet has a TON of form fitted noise reduction foam that must then squeeze the water out of.

I had a good 3" of water in rear floorboard plus what was saturated in the foam.

[amarcocazcarra]

I had to replace the rear right window regulator motor as it was not working. It turned out that the compartment was completely filled with water as the drain was clogged. For years it had accumulated rainwater. Perhaps the moisture could be coming from that point. I recommend that you check the window compartment and perhaps there you will find the origin of the problem.

[whyzee125]

Originally Posted by Bims328i

The sunroof deal for these vehicles is kind of problematic. Even if the sunroof drains appear to be working, the trough can become inundated with water.

If in any case the water builds up above the front edge of the water guide it will just spill over.

The rear portions side guide is even more shallow. Maybe an inch if that. So the rear has two narrow channels with this plastic sub assembly that attaches to the rear guide which has the outlet port to connect the rear drain tubes.

If you park your car on an incline it will favor the rear drain section. Decline, it will favor the front section which is deeper.

I had water build up on my rear passenger floorboard over months before I made the connection that it was in fact the sunroof drains.

Something to do with my passenger side as it really needed cleaning.

It could be a number of things but in my case water was spilling over the rear guide and trickling down the middle pillar.

Even after I had them cleaned, if you pour too much water towards to rear section it can spill over onto the headliner.

I dug around through real OEM to see if maybe my car was missing some seals but no.

There are actual gaps you can reach your finger up and over the front and back door into the guide of the drain tray.

Even if they drain if the car has been outside most it's life it is a good idea to clear all four exit ports. They build up a very minute but gradual debris gunk which clogs up proper draining.

I had some issues with drivers vapor barrier (after noticing water drops on the black kick board panel with "BMW" on it after heavy rains)

Then sometimes would get water over the rocker trim panel and onto floorboard.

Later, I left it level one day at work and come out, there are two small puddles on front mats.

Then water began to pool up on rear passenger floorboard. Would sop it up dry then another rain it would get soaked.

The thing is, the carpet is not like most other cars. No, this carpet has a TON of form fitted noise reduction foam that must then squeeze the water out of.

I had a good 3" of water in rear floorboard plus what was saturated in the foam.

Holy crap that is a ton of water leaks. I'd be concerned about mold after all that.

[Cal122]

Would also recommend removing the subwoofer on the floor while you're in there and checking for water. There's a sunken area for water to pool (and a drain plug to the underneath of the car) even after you think all water has been cleaned up.

[Bims328i]

Originally Posted by whyzee125

Holy crap that is a ton of water leaks. I'd be concerned about mold after all that.

It's been fine since. Mainly needed to get the water out before it sours the carpet.

I do ride around with a damp rid container to pull any additional moisture out but the cabin still smells nice and fresh.

[whyzee125]

Originally Posted by Bims328i

It's been fine since. Mainly needed to get the water out before it sours the carpet.

I do ride around with a damp rid container to pull any additional moisture out but the cabin still smells nice and fresh.

I do the same lol Tennessee weather is nasty and makes everything modly!