I am looking for some help. I have a 2011 e350 w212 and I have had an issue with the front driver side carpet getting wet. It's a second car so it's not driven very much and it is parked outside though not under any trees. My first assumption was the sunroof drains which were draining slow when I tested so I blew them out, tested, and I thought the issue was solved. The next major rain I have the same issue. So I test the sunroof drains again and the drivers side is draining slow so I clean them again this time from within the fenders. Enter winter, we have a big snow and it happens again so I test the sunroof drains again, they are draining slow and the rubber is very hard in the wheel well so I trim a bit off the end of the drain opening inside the front driver side fender, test, and everything drains perfect now. I also clean the drains by the windshield wipers and test them. The only thing I do notice is when I drive around and make turns or sudden stops I can hear a sloshing sound from what appears to be the dashboard area by the drivers side. I can't figure out where that is coming from. We have another big snow, and after it melts I find the front carpet soaked. I test the sunroof drains again and they drain normal. I have no signs of water staining anywhere on the headliner or anywhere on the sides. I pull the carpet out from the drivers floor and find standing water around the drain plugs. After I clean that up I checked the back seat and found the carpet under the floor mat in the driver side backseat damp. I dried it out as best as I could, sat in the car, ran a hose over the car for about 30 minutes without any intrusion. I hit the doors, the windshield, the sunroof, the trunk, and the hood. Nothing. We had some rain yesterday so I went out and checked and again there is water on the floor by the drain holes. I have not put the carpet back in yet since I am still troubleshooting this so I put a go pro in there to record where the water is coming from. It appears to come from under the black plastic housing that the wiring loom runs through down along the outside edge of the floor. I couldn't tell where it was coming from after that so I dried everything up, lifted that up to prop it up for a better view, and put the go pro back in there. Left it overnight but there was no water this morning. Either it didn't rain enough to trigger whatever this is or I changed something stopping the source of the water.

I am at a loss right now. I dont see any signs of dripping or staining on the metal from wanter. I don't see anything along the seals either. Any help is appreciated because I am running out of ideas.

 

This is a bit of emergency because water egress can swamp your F-SAM into a door-stop.

Standard water leaks are:

• Loose windshield polyurethane glue
• Open roof metal joints
• Discharge conduit overflow (rubber tip!)
• A/C condensate drain (Courtesy OldMan')

The swampy carpet humidity helps oxidize near by GND post connections AND the CAN bus-bars on front doors thresholds.

By all means DRAIN/DRY the pool ASAP.
Then pinpoint the source using bottle of water from the bottom up.
Use a tarp (or shipping tape) to cover roof joints...

 

When I had that it was the hose that is to the upper right of the accelerator pedal. It connects the AC unit to a drain under the vehicle. Shockingly large quanity of water.

 

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Thanks, I have not checked that one. It will be the next thing. Would that still leak if the car hasn't been driven?

 

As far as the windshield and roof, if that were leaking I would think there should be staining or some dampness around those areas which is why I ruled them out.

The discharge conduit overflow, I'm assuming you mean for the sunroof which I have taken care of already.

A/C Conduit drain, thats the next thing I am checking.

 

I have an update with more questions but no answers. I checked the AC drain line and that is not clogged, while checking it hough I noticed that the foam padding that is there was saturated with water going at least 1/2 way up the height of the tunnel. I dried everything out as much as I could, I suspect the random small puddles of water were from the water draining out of that padding. With more disconnected I went ahead and sat in the car while someone was spraying the car from the outside. The good news is that this time I could visably see water was coming in. The bad news is I can't tell where. It appears that it is coming in from the back seat somewhere. I noticed water appearing in the grooves on top of the black plastic floor vent housing that goes under the seat. I have the part disconnected that goes from under the seat, through the drivers floor, and up to the dash. I checked all the door seals and couldn't find anything remotely wet. I also checked the trunk, I did find a couple spots of water in the spare tire well but nothing remotely equal to what I am seeing in the drivers side. The car does sit nose first on an decline so if water were coming in the back it would move to the front.

At this point I don't have the room to start stripping the whole interior (no garage). My question is if anyone has any ideas on where I should check next. If not, this may be getting to a point where I have to involve a shop which I fear may be more costly than the car is worth anymore.

 

That's good research progress !

Is this a sedan, right? Not a wagon.

• open the rear trunk
• observe the rubber seal
• it goes from side to side
• Look at the space between rear windshield and rubber seal...
• This space across the car width acumulates water while home, right?
• that water needs to be released somewhere....
• likely inside the trunk rushing towards the front floor space.

Hope this helps.

 

I might try turning the car around in the driveway, see if that changes anything,

 

Based on your existing troubleshooting already done...........

Low probability, but possible water leak source at driver side.

Front SAM plastic fuse box housing gasket has gone bad.....


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The opening of this front SAM fuse box at firewall , at driver side under steering.....is in red circle.



Good luck........



-------------- Right Hand Drive Car - RHD ---------- mine

Rusty stud of Front SAM fuse box, from water which has no way to drain out.

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Buying time........minor water protection ...LOL




This is where that opening to firewall at front SAM fuse box plastic body...you can see inside the car. The grey wire with yellow tape is spare wire I placed inside the car.




More water/rain drip protection......... for front SAM fuse box.
Crude but it helps


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Good luck finding the water leak...

 

We did not have any rain last night but I had a large amount of dew on the car this morning. I did what you suggested regarding checking the seals but I didn't see anything wrong. The seal looks good, it wasn't holding any water. I used a hose on slow flow to test and the water hits the seal, gets directed to sides and flows out through the channels and out the bottom. I also didn't see any water in the trunk this morning. I checked all the carpets in the trunk (bottom, sides, and reached in to check the sound deadening behind the panels) and none of them were wet either. The minimal amount I saw in there yesterday would be way too little to be the source of the water. It couldn't have been more than bottle cap full. With that done I checked the front and I did have new water in there. To be fair, I had left the HVAC drain hose disconnected so I could let that area by the tunnel dry better but I did see signs that water had been dripping down from where the hose connects under the dash. It's strange to me because I have not driven the car since all this started (and not much before that) and the ac has not run for more than 30 seconds in the last few weeks so whatever water came through there was much more than would have been generated by usage. Where does the water originate that comes through that hose? Is it from the coil or is it from the outside? I am really beginning to wonder how much of this is new water and how much is the foam still being soaked. I am not sure I can tell anymore. I think I've been chasing this problem for too long now. lol.

Anyway, I dried up what was there, re-attached the hose and I guess I'm back to a wait and see for tomorrow.

 

I had not thought of that one. Upon visual inspection nothing looked rusty or wet in that area but how did you go ahead and test for the leak? Just poor water on it? It being the fuse box I am a little hesitant to just do that. Any advice is welcome.

 

Best is to find wetness is any, on the driver under the steering side ...around the opening hole for the Front SAM wires. Which you said you tried and found all dry.
If there is wetness there, it could be front sam fuse box.
I can't remember the grey insulation at that hole ( interior side ) is the water wicking type of insulator or rubber based.