2014 Mercedes C250 Passenger Footwell Leak from Car Wash

After going through a recent car wash, I discovered soapy water had entered the cabin in the passenger footwell. Pulling the plastic panel underneath revealed that the matting between the glovebox and the plastic panel was completely soaked. Testing the sunroof drain revealed no issue there, it drained correctly.
I believe the issue to be a poor fresh air inlet design by Mercedes.
If you find that this leak occurs in your C-Class, this could be your issue, especially if it seems to happen intermittently. It's more likely that you went through the car wash or a torrential downpour in cool weather where the blower cover may have been in the closed position. Today happened to be the first bit of warmer weather we've had around here, so I know that blower cover was wide open.

[nes]

Thank you I have a 2013 C250 same issue but it’s on the driver side.
This should be an embarrassment to the MB design engineers.
They have used this design for many years knowing this happens.
I’m disappointed.

[paulraulerson]

Mine was doing this ! Thanks for the info ! I was lost

[DomTremendous]

Hi. I have a similar issue. I watched your video and found the same issue with my car. Shocking design. I've since found a other issue. I've removed the roof lining and I can see outside through the sunroof runner.

[guyelsenburg]

I just picked up a 98 clk230 took it three the car wash and this happened to me also I had the fan on while I was in the car wash ill have to go threw next time with the fan off and see if it happens again

[TanyaScorpio]

I'm experiencing the same issue. I did have my battery changed by AAA a few months ago and i really haven't been driving the car and using my other car.
I'm wondering if possibly they did not snap the cover on the battery and hence my passenger side carpet is wet... hum
Also the last rain i noticed my car rubber mat was wet so it's definitely coming from the front.
Thanks again I'll check this out.

[oRuisuu]

Mine is missing the clamps for the sides one looks like it broke off to 🤦‍♂️i only have the center clamp but that is that issue right there lol

[Renicus]

@CrazyCal18T Hey Bud. Did you ever find a fix for this? i have a 2013 c350 that i bought 2 months ago and its doing the same thing

[conormcgregor]

Not a design issue this happens to lots of different car makers. And it is susceptible to happen to any vehicle that has a drain port.
I have a 2011 c300 my car is immaculate I wash it hand dry it I do all the mechanical maintenance too.

This guy making the video is misleading you to believe it's because of the ac system sucking it in.
Well that's from a clogged drain some people have this issue at the sunroof drain location some people have this issue at the windshield drains Location

That area where the air vent is by the battery has a rain channels and they can get clogged by leafs and dust or algae ECT.
If you look in there better there is a spot where the water is supposed to drain out down under the car thru the fender.
You need to use a pressure washer or an air compressor and blow it out in those ports really well.
I spray them every time I wash my car.
I never have this problem I never use the automatic wash. You need to make sure when you wash your car that you aim at the lower part of the wind shield and spray the small vents on the corners, (he does point out the smaller passenger side corner vent on this video briefly)

If your a person who goes to the car wash and you dont spray the leafs and debris off up by your lower windshield and near the wipers this stuff falls thru that small vent on the bottom corner of the driverside and passenger side, you should spray that area Everytime you wash the car aim the water nozzle directly at it and if you keep up with it you will never have junk in there for the water to soak into and create algae and collect dust and get backed up and clogged.
It's common sense that if you own a car you will have upkeep and maintenance or preventitive maintenance on things changing filters cleaning parts ECT.
This is definitely considered preventative maintenance and it's something you need to do for yourself and no one will just do for you.
Every car has slightly different locations and designs when it comes to doing any job, even just cleaning the car can be different from one vehicle model to another. You need to learn about your car not just point fingers at the car manufacturer and cry and complain all because you don't know how to wash a dam car.
Iv seen this issue before on customer cars. And the cars are always the ones where the owner either always just goes thru the automatic lazy car wash or washes the vehicle and never sprays down these vents and across the whole bottom of the windshield and blow out the leaves and dust and grime buildup. normally they don't dry their car either, and they have dusty dirty door jambs like the guy who made this video and probably like the people complaining on this video too lol.
Look at this video of the one we are commenting on, look at the guys door jambs down below the door hinges in his car! look at all that dust and dirt he leaves in his door jambs....
That's not from one or two weeks of driving that is definitely built up over time, so just think what those vents look like if he can't even clean dirt off his car in a spot that is visable and easy to clean.. That is lazy...LAZY!!!!
When ever I wash my car I always take a rag after I dry the paint and exterior body of the car and the windows, then I open all the doors and pop the trunk and hood and I wipe out all the jambs and get them dry my car never has that kind of buildup.

With those drain ports you get a few leafs or seeds in there and dust then the water going thru slows down more and more eventually it gets coated in algae and the hole gets smaller and tighter and eventually you have a clogged drain port.
That is your lazy a55 problem not mine.