How to Clean Cowl Drains on Mercedes S550

This is a 2013 Mercedes Benz S550 w221 model which belongs to my employer Dr Soap. If you experience wet floorboards inside your car, I show you what steps you need to take to prevent this from happening. There's an important water drain system Mercedes put on the S550 to keep the firewall dry as well as keeping water from entering the cars internal air conditioning system. You'll need to focus on 5 drains along the cowl section just below the windshield where the wipers are connected. Keeping these drains free from leaves and other debris will help them to do their job keeping your car from flooding and destroying expensive components which make the S550 the highest quality car on the road today.
UPDATE 11/14/2020
I mentioned using a fish tape to push debris through the cowl drain. However, I've discovered the best way to clear them is to use an air compressor Kobalt blow gun that has a blue beveled tip on it and blow from the bottom of the drain upwards. Doing this will blow any debris that's in the drain tubes out at the top. I use a 200 PSI 4 Gallon Air Compressor with a Kobalt blow gun attached to the air hose. I found out this is the method used by dealerships when the car is still under warranty.
Before using a blow gun as described above, make sure you watch the below video which shows you how I modified the drain tubes in a way that accommodates the Kobalt blow gun.
This other video I made will show you how to modify your drains for better flow which can help prevent them from clogging. You'll definitely want to do this, It only requires about $10 at your local hardware store and is very effective for keeping water flowing through your cowl drains (don't skip this or put it off, its important if you park near trees) Mercedes should have did a recall and made this correction for owners but didn't, so you have to do it:
How I modified the two outer cowl drain tubes for better drainage and to accommodate the Kobalt blow gun:
• How to keep water from...
Here's how I keep leaves and other debris out of the cowl drains:
• Mercedes Cowl Drain St...
Look at my other how to videos for helpful tips on keeping your S550 Mercedes in top shape. Subscribe to this channel and click the small bell to be automatically notified when I upload a new how to video about the S550 W221 Mercedes Benz.

[@sbmate1]

Thank you so much. I have a used 2011, went to the car wash, and water came through. I think I can fix it after watching your video.

[@eddiesandoval2234]

fond out why I had water on my passenger floor thank you!

[@ALEX-wz8ts]

Omg your a life saver...best video on youtube..I just unclothed my drains..I was going nuts I coudpent find them..atleast 1 gallon of water poured out the bottom of the car

[@MercedesMechanic]

Watch my other videos of how to keep the leaves out of your drains, you can find links to those videos in the description below this video. Once you do that you will not have this problem anymore.

[@llamamanism]

Thanks for this information. Just what I needed

[@MercedesMechanic]

The only way you’ll unclog the cowl drains is to get an air compressor about 200 psi with a air blow gun attached and open your fender well behind both front tires. Insert blow gun up into bottom of drain tube and do short air blasts until nothing comes out up top anymore. Then try to fill the drain with water up top, if it’s fully clear it will not overflow with water. Watch my other videos that show how I prevent leaves from ever getting in these drains.

[@mohammadsalimullah6323]

Many thanks Buddy!

[@HappyHealthyOutlet]

My ML350 was parked for almost a month and after heavy rain, I found water on driver floorboard. The front drains are not clogged but when I poured water on the driver side sunroof drain, it comes under the steering wheel cover. Car starts but SRS, back camera, DSR, SOS, turn signal, and washers are not operating. When I tried to clean the sunroof drain with the drain brush wire, it goes all the way down, but still water coming out under the steering cover. It seems water got into the wiring under the steering, and I am really worried it might cost me legs and arms.

[@charlesbartholomew2910]

Yes, even earlier....2004 S500

[@nickvasco2135]

Just last week my blower stopped on my s350l.I’ve seen a few videos and believe the issue to be the blower.I also checked the drain holes and found the one on the passenger side (UK) was blocked and as I feared the footwell area was wet.So tomorrow I will remove it and see if I can save it.Appreciate your upload.

[@MercedesMechanic]

Glad to help, these cars are made to park in a garage and not anywhere near trees.

[@tanniewill1986]

Thank you 😊🎉

[@MercedesMechanic]

No problem, did you have a problem with yours, what model do you have

[@moleaaurel4714]

Wasn't it more advisable to use the tips given in the video? It was really beneficial to show how it is done.

[@MercedesMechanic]

Yes

[@solidbriskjatt]

You have info on the drain for ac being plugged up?

[@MercedesMechanic]

No sorry

[@ppg19782]

I got here by looking at a YTvideo on MB S65 AMG in which you left a comment regarding the AC drains .. There is one for sale for $30K and it has 90 K original miles supposedly. Dont know if it would worth the buy... By reading the comments on the S65 that you commented it seems that the maintenance will be costly. It went by 3 owners. In the same website there is another listing for a 2011 CLS550 for $16,900 with 38K miles...2 previous owners... The one that I really am interested is 2012-2018 CLS63....but they are about $40k with low miles.. Appreciate your recommendations and input.. Much blessings 🙌 Ty

[@MercedesMechanic]

$30k for the S65 isn't bad but at that price I'd question it. That price says to me that its probably an early year W221 like 2007 or 08. I wouldn't worry too much about the 90,000 miles because its a V12 so thats about break in for it provided it was taken care of. Its a bit pricy to repair as the hydraulic suspension and coil packs are a bit expensive and likely need attention at 100,000 miles. Spark plugs alone are around $1600 just to buy the right ones. I'd say go for it but unless you have money laying around to fix it, it could become a lawn ornament for you. That's likely why the others got rid of it but its hard to tell. The S65 is worth owning because its a well built machine hence the $200,000+ price tag. You won't find a better automobile to own as long as you can afford the repairs when needed. It'll also save your life in an accident and was specifically built for that purpose which is why millionaires rode in them. You don't however have to be a millionaire to own it though, just an occasional repair bill in excess of $10,000 here and there and it'll continue to take care of you. I don't have an opinion on the other models you mention and only focus on S Class because they were made better than all their other models.

[@MercedesMechanic]

The S65 has suede leather for a headliner, its real sweet in every way. Mercedes put every option on that one, people who bought the S550 had to pay for those options if they wanted them but they were all standard on S65.

[@theologicallife.....1103]

Thanks for the info, my blower motor comes on all by itself and goes off intermittently. Just had the compressor changed and no air, the AC is showing "off". Would this cause that issue?

[@MercedesMechanic]

Not sure but water intrusion in behind the dash and then in the foot wells causes chaos. Thats why its important to keep the drains working properly. I'd take it in to Mercedes and let them do what they do best.

[@MercedesMechanic]

Its not really a fix it yourself car like many other brands. Its complicated.

[@MercedesMechanic]

If you drive an S550 W221, the car has 4 fuse boxes and relays out the ass. Sensors galore and so many other small things that can go bad and cause a whole lot of chaos. S Class is the best and not so much for poor people who cannot afford the dealers repair costs. Crash tests of the S550 is why I drive one because you're pretty much guaranteed to walk away from an accident without a scratch.

[@Dana-vx1dp]

@christine Richardson my s550 was doing the same thing for about a week and then just stopped working all together... I actually checked everything this video is showing and found out that my ac blower motor under glove compartment was full of water... I brought another one for 50 dollars off ebay plus a 30 dollar resistor because the water had damaged both.... a T20 wrench and about a hour worth of work solved my problem... I hope you get it taken of....

[@theologicallife.....1103]

Damian Cornick thank you I’m going to look at it today I also replaced mine too about two years ago. You would think they would be able to find a way to make that area more secure

[@issacbrown7485]

Having this problem today after heavy rain last night. Had the heat on this morning & heard a static/gurgling sound like water rushing so I turned it off. Also heard some water near the wheel which I realize was coming from the drain tube. Then realized the passenger floor was damp. Got fish tape but it only goes so far into the curved drain from the top. Trying to get the fender liner off so I can clean it from the bottom. & also had a lot of standing water in the middle one with the mesh cover, I vacuumed it out and it seems like more water got into the floor board, any help?

[@MercedesMechanic]

Watch my other videos linked in the description of this one, those videos will tell you what you'll need to do.

[@issacbrown7485]

@@MercedesMechanic thank you sir! Ironically I just saw your post on benzworld. I got all the drains cleaned out but now I just need to locate an air compressor to shoot some air through the bottom. The waterfall drain in the middle was clogged right around the small drain hole.

[@MercedesMechanic]

Watch this one and read what I did in the description of the video. Once this modification has been done, cost of about $10, its very easy to blow out the two drains from beneath the car and it'll save you from having to open up your fender wells. Those drain tubes do not belong in that little pocket behind the front tires, it was a bad decision by Mercedes to do it that way. kzbin.info/www/bejne/iIKuiImaZ8xgf5o @@issacbrown7485

[@hollymunford6857]

What is a fish tape?

[@MercedesMechanic]

Its for measuring fish after you catch them. Only kidding!!! Don't use a fish tape because it doesn't go through the drains and if it does, it won't clean them out. You have to use an air compressor to blow the drains out from the bottom of them by blowing upwards and all the crap in them will fly out the top of the drains. Merry Christmas

[@OMGWTFLOLSMH]

Ever hear of google? Takes 5 seconds to search and see a picture in Google.

[@lanceappleyard3055]

I have a water leak in the trunk of my W221. A video would be welcome

[@MercedesMechanic]

Never heard of that problem but sounds like a seal somewhere is letting water get in.

[@lanceappleyard3055]

@@MercedesMechanic BTW, on your video for the front, The drain from the "blower intake" area is a small drain that leads to another cowel located under the Aux battery. If there is a buildup of debri under the battery it will clog up the "secondary" drain that clears the water from the blower intake. Just FYI. A air hose will not clear out the secondary drain as they are not directly connected.

[@MercedesMechanic]

@@lanceappleyard3055 on the 2013 w221 the AC air intake has a small drain hole in the bottom of it which drains into its own drain beneath the car. If you look carefully with a flashlight beside the main battery, you'll see the water draining into a small cup like drain tube that goes beneath the car. If you think its clogged and you dont see stuff clogging it, you can blow into from top because it goes from being small to large as it exits beneath the car.

[@MercedesMechanic]

@@lanceappleyard3055 If the secondary that it leads to is clogged, it'll likely just overflow and drip below the car.

[@lanceappleyard3055]

@@MercedesMechanic Different design on 2008. I just cleaned mine out so thought I would share.

[@russwar12]

Fishtape 200 euro 💀

[@MercedesMechanic]

fish tape won't work for cleaning out the drain, you have to use compressed air through the bottom of the drain tube and blow upwards.

[@Miamiflow885]

Can you talk slower so i can slip comfortably back into my coma

[@sethbracken]

I had to double check I had actually put it on 2x