survey1

Hello all,

I'm thinking that my sunroof drains may be overflowing into the cabin. After a heavy rain, when I enter the car all the windows are fogged up.....to the point where the defroster is needed to clear the windows. Had dealer check drains as car is under warranty and said they were slow, offered to clean them for nearly $300 and said it "should" fix the problem.

Is there any way to say for sure that this is the problem and can you think of anything else that may be causing high humidity/water ingress in the cabin after rain?

Any TSB's on this issue? How hard are the drains to clean DIY and where would the water be pooling inside the car? I can only find slight dampness by passenger side front foot well.

new550

See this thread...I have to clean these every year


https://mbworld.org/forums/s-class-w...-clogging.html

mrbobby

I would focus on getting it fixed ASAP before the water ate a SAM.

survey1

Can that cause leaking inside the cabin of the car? Were you seeing moisture on the inside of the windows?

new550

Yes, rain overflows the drains when they clog... you'll get water on passenger floor up behind glove box and in blower motor ducts/housing

survey1

Bingo..........I just inspected them and the passenger side is clogged and/or maybe disconnected at the lower base. The water is coming from behind the inner plastic fenderwell cover, instead of from the drain hole behind the wheel. The drivers side looks clear but flows slowly. Was noticing dampness on passenger floor area.

How can I snake the entire duct without poking it? I cleared out the opening but the line is clogged somewhere.

new550

I loosen the fender well liner and clear out the little "gutter" attached, then use a thin coat hanger or wire to push down from top to bottom. I've tried a compressor to blow it out as well, but didn't seem to work well.... just a really poor design, as it narrows from top to bottom and exits via the silly "gutter" instead of directly emptying to the wheel well. if you attach a piece of twine to the wire and push down and pull out bottom, you can then pull in and out a bit like dental floss... you'll be good until the leaves fall next year....

DubVBenz

Nice to see at least one major flaw was retained from the W220

survey1

I got a box of 20 pipe cleaners at a fabric store today and I'm going to try to tie them together and snake the drain fully clean. I couldn't find anyone who carried a 6 foot pipe cleaner or anything was made for this purpose.

survey1

I wanted to let anyone know who has this same problem that I hooked all 20 pipe cleaners together, forced them down the train with needle nose pliers, pulled up with my wet-dry vac running and was able to pull up a huge mound of leaves and sticks. The drain is now working for less than a $1 worth of pipe cleaners. I'll have to check and make sure the moisture issue has been resolved inside, but the drain is working fully for sure now.

survey1

Wanted to report back that I'm still getting moisture inside the car after heavy rains. (I'm guessing) .....because of the gap at the beginning of the drain line where the windshield gutter dumps, it will overflow onto the firewall if pushed beyond capacity. I opened the hood to find it wet after a storm, yet both lines drain as designed when tested.

Any other ideas?

KNBS550

And the 1992-1999 W140 S-Class. Totally unacceptable considering how long this poor design has been around and how much havoc it's caused for S-Class owners. My Lexus has a much larger drain size even though it's smaller than the S550.

KNBS550

Have you considered drilling a larger hole in the fender liner where the water drains out? The hole design seems awfully small to allow a sufficient enough flow rate in heavy rains.

survey1

That would look horrible.

Any other ideas?

KNBS550

Not sure what you mean. The hole is in the fender liner is aft the front wheels and you wouldn't even see it, since it's so small.

survey1

There is a tube that connects to the rear and it would also have to be replaced for this to work, plus you can see the outlet just walking by the car.

alx

Driving a pipe cleaner/ hanger wire/ etc will unclog, but will also dislodge the drain pipes and will cause an internal leak. It is bad design.

You want to use a thin but rigid wire (like the blade the electricians use to run wires though walls) and carefully push your way through. Also you want to make the exit nozzle in the fender bigger as it does clog easily.

Appearantly there are no leaves and tree debree in Europe. VW drains are even worse.

1bad540

mine was clogged after buying it cpo I was also getting water in the pass footwell area. It fried domething after a heavy rain and the car needed to be towed to dealer. I use a shirt hanger every so often.

s550hollywood

Use an electricians fish tape with a little electrical black tape over the sharp end, works well and will go through the curved drain tubes. I also just did this on my 2013 S550 w221 because the little pocket behind the little hole where the the drain tubes were ending causes major clogs. I bypassed the pocket with 1 1/4 inch clear tubing cut 13 inches long and a hose clamp. You'll need to do this as the fish tape or wire hanger you push down in these drain tubes from above will only run into a dead end behind the little hole in fender behind tire. Mine drain as well as my bath tub now.

s550hollywood

Also check the little reed valve for a clog, its down inside your air intake for the AC. This video shows you 5 different drains to keep clean on the 2013 S550. It may also be the same layout as earlier models but the video will show you so you can compare your earlier model to my 2013. The video also discusses how I modified two of the drains to preform better as pictured above.