W204 Coupe - Wet rear passenger footwell! Help!

[c180081c]

Hi guys,

My W204 coupe has developed a weird wet spot in the rear footwell?!! The door seal is fine and the water is accumulating around the back of the seat runner, it’s utterly sodden in this spot but dry all around it. Any ideas?

Thanks in advance


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[clk320x]

Photo please of exact location

 

[c180081c]

Photo please of exact location

Will grab one in the morning thanks


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[markjay]

Usual culprits are hatch seal or blocked drain holes / pipes.

 

[c180081c]

Usual culprits are hatch seal or blocked drain holes / pipes.

Door seals are fine and the sill carpet is dry, it’s very strange. I don’t have a sun roof so could it be the wiper area drain holes? I see underneath there’s a vent in the under tray just below the offending area, unsure what it’s for


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[c180081c]

Photo please of exact location

Dried it out a bit but this is the offending area



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[markjay]

The water just accumulate at the lowest point then come up through the carpet.

Do you have a roof (shark fin) antenna? That's another possible source of water ingress.

 

[c180081c]

The water just accumulate at the lowest point then come up through the carpet.

Do you have a roof (shark fin) antenna? That's another possible source of water ingress.

Nope, all drains appear to be clear after inspection with the hose pipe


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[c180081c]

So this morning I had a top up coolant message, is there anything that links these two locations?


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[markjay]

You could have a leaking heater matrix or hose behind the dashboard. But then the wet patch would smell of coolant and be slightly oily to the touch.

 

[c180081c]

I thought that but there is no evidence of water in he front of the car even after pulling up the carpet, the water smells to me like rain water it’s dirty I’ve soaked most up with white roll


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[c180081c]

I thought that but there is no evidence of water in he front of the car even after pulling up the carpet, the water smells to me like rain water it’s dirty I’ve soaked most up with white roll


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Mega confused, just checked the coolant level it’s hardly dropped, maybe a sensor fault and a red herring it’s been roasting here the past couple of days


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[wu56Shoozz]

I'd say its the top corner near the Door Pillar of the rear door, that's leaking ..make sure the door is actually hitting the seal and not just lying above it.. you haven't had anything over the rear door like a sun block or anything and got caught in a shower have you?

Not related - but I had similar on my van that bugged the L out of me, so on Saturday whilst It was hot.. I set about lubricating and readjusting the door - 10mins and I was done..(Why couldn't the bodyshop do this?)

If it was the heater matrix the car would also steam up and smell of pakora..

 

[c180081c]

I'd say its the top corner near the Door Pillar of the rear door, that's leaking ..make sure the door is actually hitting the seal and not just lying above it.. you haven't had anything over the rear door like a sun block or anything and got caught in a shower have you?

Not related - but I had similar on my van that bugged the L out of me, so on Saturday whilst It was hot.. I set about lubricating and readjusting the door - 10mins and I was done..(Why couldn't the bodyshop do this?)

If it was the heater matrix the car would also steam up and smell of pakora..

While it’s been hot I’ve dried it all out, I think your bang on there as you could almost see a channel where it had got in, once dry I stuck some kitchen towel the full length of the carpet and put the heater on full, no sign of any water so I assume the coolant low warning was a red herring, I took the sensor out and cleaned it and no issues since


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[wu56Shoozz]

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[c180081c]

Ok chaps so this is where we are at, I’m slightly greyer and balder. The drains at the front are clear, the boot drains are clear, the heater matrix is fine with no loss of coolant, the carpet is completely dry throughout aside from the offending area, the door seal is perfect. I’m absolutely at a loss


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[c180081c]

Had the vax out today, pulled two pints of dirty water out of the carpet. Thankfully reassuring me that it isn’t the heater matrix but still concerned as to how it’s getting in. Are there are drain holes toward the back of the vehicle?


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[ernie]

Had the vax out today, pulled two pints of dirty water out of the carpet. Thankfully reassuring me that it isn’t the heater matrix but still concerned as to how it’s getting in. Are there are drain holes toward the back of the vehicle?


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Did you get to the bottom of this? As you are saying the water is dirty, it must be coming from underneath. A bit of a long shot, but how old is the car? I ask because there have been a few the early W204 C Classes on here and the other side with serious rear subframe corrosion. I'm wondering if there could be a problem with the mountings on yours letting water in under the carpet.

On a slightly longer shot that you may have covered, I remember an old VW Golf that had chronic water ingress in the front passenger floor area. We tried everything we could think of and then the owner remembered that a local garage had recently replaced the window regulator on that side. Sure enough, when we removed the door card, the polythene membrane was missing and the water was trickling in through the bottom of the door card.

Let us know what the solution was if you find it!


Ernie

 

[c180081c]

Hi Guys, so after it dried out I have had countless trips in the rain and countless times ive washed the car and ABSOLUTELY NO WATER. I can only assume someone kindly spilt something or ive left the window slightly open, god knows!