[efair]

The passenger footwell on my SLK 230 is staying wet. I found both rear drains thoroughly clogged, but that is all. Looking at the routing of the rear strains, I'm wondering if the water can really come into the passenger cabin from clogged rear drains?

I also removed the washer reservoir and I found only a minimal buildup where the fender meets the rocker panel - not enough IMHO to account for the amount of water.

The seal between the cowl and the base of the windshield seems intact, is this the only seal that keeps the blower dry? I'm wondering if the water is sneaking in thrrough the blower airway.

Does anybody know where the air-conditioning condensate exits?

 

[cockneyrick]

In the left-middle-right corners of the front bonnet against the bulkhead are 3 more drain points. The LH one is by far the worst culprit & will block & overflow through the heater blower under passenger footwell. Yours being a LHD will just mean a reverse of what i have said.

I got a piece of plastic coated wire & fed it down the hole as best i could, then ran a jug of water thorough. It should dump out by the back of front wheel.

Best get under the footwell & remove the cover & drop the Heater assy (search for disassembly) out while you are at it. The pollen filter is there too & will most likely be soaked & useless.

 

[efair]

Thanks Rick. I did check those three drains first since they are the most likely cause of wet floorboards; even though they appeared clear, I went ahead and removed the wheel well liners, washer reservoir, wiper arms, and plastic cowl beneath the windshield for a look. I did not find anything suspect. On your suggestion, I just now removed the dust filter and the panel below the blower. The filter was dirty but completely dry with no indication of previous moisture. The panel below the blower had just a few drops of water, and the lower bearing appears dry and rust-free.
While I was at it, I also checked the two drain holes in the door - both were clear.

It looks like the blower intake is also through the cowl, although rainwater is prevented from entering by the shape of the cowl itself - rainwater is diverted instead to the three aforementioned drains before it has a chance to reach the blower intake. If these three drains clog at their upper inlet, as by leaves accumulating, surely an overflow into the blower intake could result, with attendant saturation of the dust filter. However, that does not appear to be my case. I'm wondering what other avenues might exist for water to reach the floorboard.

- Is it possible for a clogged rear drain to cause it? I'm thinking this is not very likely.
- Is it possible that the drain inlets and tubes are clear, but the joint between the fender and rocker is clogged, causing rainwater to accumulate inside the fender underneath the washer reservoir and somehow find its way inside to the floorboard?

I guess the next step is to remove the seats, console, and carpet to find the source if it continues.

 

[efair]

Here's a picture of the drying out process. Under the yellow towel is a room dehumidifier. The idea was to make a tent to focus the effect.

 

[cockneyrick]

Another problem (which mine did this morning) is again the LH door seal at the foldaway roof join lets water in too.
This usually will soak the carpet eventually, but is a giveaway by the LH seat being wet too.
Other than that, you seem to have covered everything else anyway.
I have had 2 now (99 + 03) & both have had identical issues.
I too did the dehumidifier thing to dry em out as they are notoriously bad at getting wet if left unattended outside for any period.
Once in service, i think they cope better with circulation etc.
Good luck in finding it, but def not from rear drains :wink:

 

[efair]

I left the car out for a day in the rain with the front wheels raised on jack stands. Again the carpet got wet. So I knew I needed a more thorough examination. I was planning to gut the interior for repainting, so i started on that, and afterwards I was able to pull the carpet up to a much greater extent than before. The carpet was thoroughly soaked again. It's impossible to remove the carpet entirely without much much much more work, so I just raised it as high as possible so that the foam blocks glued to the back of the carpet couldn't get wet again while testing.

I discovered a perhaps significant issue with the seal between the windshield and the cowl - it was upside down! This seal is not symmetrical so orientation does make a difference. I re-oriented the seal.

Ive dried the car out again and performed some preliminary testing and found no leaks - but I've not soak tested it with the garden sprinkler or in the rain yet. More coming.

 

[efair]

Rick, do you mean where the roof meets the windshield? Or where the roof meets the rear window?

My seats are staying dry, it doesn't appear to be dripping from the side window seals

 

[cockneyrick]

Rick, do you mean where the roof meets the windshield? Or where the roof meets the rear window?

My seats are staying dry, it doesn't appear to be dripping from the side window seals

Yep the leading edge between windshield top & roof front. Open the door & see the extra lip on the door seal here. Gets blocked up too.

 

[efair]

I gave it a soak test today - again with the front of the car raised and the carpet lifted up on the passenger side. About 30 minutes with the garden hose. I put dry shop towels all around the floor and under the dash before starting. I also removed the cabin filter and the panel that encloses the blower motor.

It appears the water is entering through the air conditioning because the towels directly underneath the blower were saturated. The other towels were downstream so to speak and just barely wet.

So I took the cowl off again and I could see where the area around the fresh air intake, and the blower, was wet. Water should not reach this area but it is!

So I'm guessing the seals in this area are bad - either:

1) the 5-foot- long seal mentioned above between the windshield and the cowl, or
2) the 8-inch seal on the cresent-shaped portion of the cowl -between the cowl and the bodywork, or
3) the small 1" foam-like seal that fits between the windshield and the above crescet portion of the cowl.

I put some silicone sealant on #1 & #2 and will soak test again this weekend.

 

[efair]

Rick,
I did clear that seal (and all the hollow ones like it). It didn't appear to be blocked.

 

[cockneyrick]

I gave it a soak test today - again with the front of the car raised and the carpet lifted up on the passenger side. About 30 minutes with the garden hose. I put dry shop towels all around the floor and under the dash before starting. I also removed the cabin filter and the panel that encloses the blower motor.

It appears the water is entering through the air conditioning because the towels directly underneath the blower were saturated. The other towels were downstream so to speak and just barely wet.

So I took the cowl off again and I could see where the area around the fresh air intake, and the blower, was wet. Water should not reach this area but it is!

So I'm guessing the seals in this area are bad - either:

1) the 5-foot- long seal mentioned above between the windshield and the cowl, or
2) the 8-inch seal on the cresent-shaped portion of the cowl -between the cowl and the bodywork, or
3) the small 1" foam-like seal that fits between the windshield and the above crescet portion of the cowl.

I put some silicone sealant on #1 & #2 and will soak test again this weekend.

Always thought the water was getting in here, 2 of mine had same issue so is a very common problem. Cured both tho, by unblocking drain points in front corners of bonnet hinge area. Long coated cable pushed down em.

 

[efair]

I gave those two a good cleaning first thing, and I believed it helped with the majority of the water. However, my OCD testing revealed continued dampness. And the equipment panel showed what looked like chronic moisture.

I'm happy to report, after two hours of this, the interior is staying dry!

Moral - if the drains aren't the culprit, clean and silicone the seals if they're worn - or just replace them.

 

[cockneyrick]

Can you put up pics of your newly siliconed seals for others to see what/where needs doing.
This is a major & common problem for all R170's

 

[efair]

I've already re-assembled them, so I can't take pictures.

However, here is a screen grab from EPC.

#40 and #50 are the seals where I added silicone. There does seem to be a small part missing from this diagram, I'm not sure why.

 

[abakxm]

Dear Friend: I am owner of a 2003 SLK 320. Im writing you from Chile southamerica and as far as I see, you had a problem about geting the floor wet. I didnt get all of your chat within this forum so I would really apreciate if you can tell me some things more in a basic english. Today, after a rainy day, I found while I was driving that the copilot floor was wet with some water drops coming down from the glove compartment. I opened the below the glove compartment, where is the cabin air filter, and I found another black plastic box which I dont know what is it. I opened it and it was with little water...so I guess thats where the water drops came from. Did you had the same problem? What did you do to fix it? Thanks a lot. Sincerely Anton.

 

[efair]

Yes I had the same problem. Below the windshield wipers there is a black plastic "cowl* that was leaking rainwater into the black box - the same one you opened. I removed my wipers and the 7 screws that hold it the cowl, and I used silicone sealant on the edges.

 

[abakxm]

Thanks 4 the answer...do you have any pics to see how you did that? what u removed.

 

[efair]

No pictures, sorry.