We've had some heavy rains in my area recently and when I checked the drain holes at each corner, at the base of the front windshield, I noticed they were full of water. This made me panic a bit because I've read about water intrusion into the cabin from similar situations and causing electrical issues, especially with the W220 series vehicles.

At first I took a coat hanger, unwound the coiled portion around the hanger hook area and turned it into a long metal wire to stuff it into the drain holes to clear them. I had success on the PASSENGER side, but the DRIVER side still had water and wasn't draining. I tried to unclog it some more by jabbing the straightened wire coat hanger through the drain hole and after half a dozen attempts, still no luck. I poured in more water to see if it was draining at all and it was just sitting there. I even tried blowing into the drain to see if it would push the debris out and still nothing. Frustrated I gave up to sleep on it.

The next day, I go to Lowe's and ask for a small radius wire brush type tool that was flexible enough to go down curved pipes. The guy shows me this thing called a DRAIN WEASEL. It is a long plastic rod that has velcro like strands at one end to catch any debris. $6 later, I stuff the DRAIN WEASEL down the DRIVER side drain, pulled it out and voila...it caught a good chunk of compacted dirt that was stuck inside. I did this multiple times to make sure the drain was completely clear of any dirt or debris. I then flushed the drain with water. The water flowed unimpeded through a weep hole at the back of the fender liner, behind the wheel and to the ground.







I'm usually OCD about clearing leaves and pine needles from the windsheld and the car is parked in a garage so I was a little surprised to have the drain plugged as much as it was. Anyway, just thought I'd share this with the forum in case you had similar issues.

 

KNB...thanks for the info.

Hd

 

No problem, you're welcome!

BTW, I didn't mention in the post that the drain weasel has a handle at one end to rotate the brush at the other end. The whole thing is flexible enough to bend around gradual corners and the 'brush' rotate as it collects dirt and debris.

 

I just did this last week but this device you got seems to be an awesome alternative to me also using the wire hanger. Thanks man!

 

Great post KNBS550. Alternatively, you can also use Fish tape, an approx 3 to 4 foot long portion is good enough. I taped off the sharp end of the fish tape with electrical tape so it doesn't scratch the plastic tubing inside. The fish tape is very strong steel, yet flexible enough to maneuver through turns and clear up clogs. I do like the flex/handle of the weasel. Here in Vancouver BC, I couldn't find a similar item at the retail level.

One added tip for you who are cleaning out your drain pipes... is to also (partially) remove the fender liner (just a couple of plastic clips), once exposed, due to the debris clogging the weep hole you will notice large amounts of debris/sediment at the base of the weep hole, at the bottom of the fender lining and also inside where the side skirt resides (there is a small corridor/gap that runs perpendicular to the skirt). I was amazed at how much debris accumulated in there overtime. So removing it is a good ideal esp if you live in damp climates like I do and if you park outdoors daily like me. I clean out the pipes twice a year now.

Note, there is also a 3rd drain pipe that drains water from the hood.

 

sorry double post..

 

 

 

 

Yes. In addition, check if sunroof drains (front/rear corners) drain properly.

 

 

Hi,

Just a tip for unclogging the two side drains (90 & 100) . Use a 5-6 ft fish tape rod. (Used for pulling wire through conduits, behind walls etc). I snipped off 5' of it and keep it for this purpose. Taped one end with electrical tape (to round off sharp edges and to protect the internals of the plastic drain pipe). Insert fishtape into drain (pushing up and down) and you'll notice the water will clear out from the front wheel well (behind the front tire). Theres a small cutout where water drains out. I went an extra step and also removed the rear portion of the wheel well to gain access behind the pipe and physically remove the debris blocking the pipe. I found a ton of leaves and buildup over time.

I've got a 2009 S550v (presume its the same for MY 2010-2013) and have noticed especially on the passenger side ( part # 100) the plastic black molding on the bottom runs the length of the windshield directing water to the pipe (100 & 90). But I have noticed the water doesnt actually flow 100% of the water into drain 100. So, i cut out a lip (using a plastic water bottle) to funnel/direct 100% of the water down the pipe. Easier to show if I attached a photo.

This wouldn't be a problem for us S-class owners if Mercedes had used a finer grid mesh, so larger debris cannot flow into the two drain pipes (part 100 & 90).

By the way, my dealer wanted to REPLACE the drain pipes (parts and labour over $600) cause they said it cannot be unclogged. Only replaced. I call that BS.

Cheers

 

 

Good luck! And use a fish tape cause its strong & flexible enough to push through the drain pipe.

 

I used to clean out mine every few weeks, like others have said a fine wire up and down is enough to keep them flowing if there not stuck already. I had water intrusion in the car when i had 1st got it....pain in the a$$.

 

What if I just removed 100, 110, 120, 140 and 90 of the diagram on my w221 and just let the water drain freely wherever it wants?

 

IMHO would not recommend this.

 

I found a pocket molded on the rear side of the fender wells which #90 and #100 flow into. This pocket was full of crap which was not allowing water to escape through the small hole on face of fender. I took this picture behind the front driver side fender well I pulled back after removing two push pins at bottom of fender. The pocket that 90 and 100 drains into is the problem, as it acts like a bowl at the end of a straw. It would be like you putting a hole in the bottom of a bowl and then funneling water into the bowl with a straw, leaves and dirt flows into the bowl, eventually the hole in bottom of bowl gets clogged up and acts like a damn. My suggestion is to take the end of 90 and 100 out of the pocket (bowl) and place a piece of clear water hose onto the end of 90 and 100. Extend this piece of hose beneath the car. This way you remove the damn all together and when you run your fish tape or weasel through 90 and 100, you'll be pushing any debris and leaves out the end of the clear tubing you extended beneath the car. Mercedes should of did it this way. They did that with 140 and 110 as when you pour water in those, it comes out two tubes beneath the car.

 

Anyone used Karcher pressure washer from the top ? Just wondering if I can blow everything out this way?

 

That won't do anything because the drain tubes #90 and #100 on the spec sheet above lead to a small pocket on backside of the front fender wells which only has a small hole which you can see behind the front tires. Nothing larger than that hole is going to come out no matter what you do. I created a fix for this in this video, once you complete this fix on your W221, you can then use different methods of cleaning out the tubes and everything you push down the drain tube will end up going into a 1 1/4 inch diameter hose and fall out underneath the car, see how I did it in this video:



Here's an image of my fix:

 

I just used pressure washer located on petrol station to see what’s happens. I put it deep as I could inside and.. go! I could not believe how much black crap comes out through wheel arches on both sides.. I also checked and drilled a slightly bigger holes in wheel arches to make sure nothing gets stock in there in the future. I think it’s best way to do it by pressure washer as manually you won’t clean it as good by just pouring the water. I’m happy with the results ! 😁

 

I discovered that using an air compressor blow gun, and blow from the bottom of the cowl drains upward will clear them of any debris that may be clogging them. Blowing from the top doesn't work because the drain tube gets narrow as it goes downward. I also made small leaf catchers to prevent leaves and other small tree debris from entering the cowl drains. These three videos will explain what I did.

Part 1 of 3

Part 2 of 3

Part 3 of 3