Water on front floor W163 2000 ML320

[Autobahner]

Hoping someone can give me some guidance... (Gilly - would really appreciate your input from your experiences.)

2000 ML320

Let me paint the picture...
My W163 has a moistness on the floor in the front drivers and passenger (less there) after a recent rain. Only moist at the carpet closest L & R front corners to the front doors. No musty smell - is new water. Truck is parked outside pointing slightly downhill. Seats (leather) are dry. Temps in 40's (not using A/C in at least a month). Today checked both front L & R sunroof drains and water goes through with no resistance. Where can the water be coming in?

I suspect the upper seal on both sides running from the front fenders going up along a-pillar across top of body over the B pillar ending at the rear of the back door opening might be tired and needs replacing. I do see at the rear of both these seals water tracks from the rear of both leading onto the rear door seals. I consider this upper seal the first defense against water entering the vehicle. Second are the door seals themselves (on the doors).

Anyone have such an experience? I'd really appreciate the feedback and possible solution.

Anyone ever replace these upper seals? Hard to do? Anything needed other than the seals themselves for the job?

A general thanks in advance for feedback.

Autobahner

[Gene Horr]

Check your AC drains.

[Autobahner]

tks
checked and is clear.

[Gene Horr]

Darn. Usually it is something simple. Then you are back to the drain lines. I don't know specifically how you access them. If you don't get a good answer then try removing the inside pillar trim parts and see from there where you have to go.

[Autobahner]

tks Gene

Sunroof drains work fine. A/C drain works fine. That's why I'm looking closely at the weather and door seals. Seals on windows look tight and flexible.

Anyone with some ideas?

tks

[mbdoc]

The only external water leak (other than sunroof) that I've seen on a W163 was from a bad windshield installation.

The sunroof drain hose could be an issue behind the "A" pillar trim.

[Autobahner]

tks M.B.Doc

Windshield is original install but will take a peek.

A-pillar is my gut thought as well. I'll take a look ASAP, maybe the connection where the sunroof drain hose connects to the sunroof tray might be the issue. With the drop in temp rubber becomes stiff and contracts. Additionally, possibly the hose (due to age) has become hard and no longer pliable (happened with my GTI) thereby no longer sealing properly to the sunroof rain tray drains.

I'm thinking sunroofs are overrated for all the crap I've been through with them. Next time - I'll think twice about that option.

Tks

[Autobahner]

Oh yea - can you pls provide me a quick tutorial on how to properly remove the A-pillar covers?

[mbdoc]

Hope this helps..

[Autobahner]

Tks M.B.DOC for the schematic.

took a look and all looks normal with the drain hoses.

I believe the culprit is the sunroof panel gasket. Gap around some edges are too large and likely allowing too much water into the sunroof rain pan overpowering the capacity of the two forward drain tubes (truck is parked slightly downhill nose forward). I know how to adjust gasket (thanks to this forum) but vehicle is 2000 and rubber is on the stiff side. When trying to adjust the wedge portion of the gasket (that which inserts into the sunroof panel) is not holding in as it should. Time to replace.

M.B.DOC (or anyone else for that matter...) - if you have any tips on how to replace the sunroof panel gasket WITHOUT removing the sunroof panel (is it even possible?) would be really appreciated as this could be a huge time saver.

Tks!

[Autobahner]

I've replaced the sunroof gasket. MB revised the gasket from the adjustable felt type oiginally installed to a nice softer rubber unit that is not adjustable but rather offers a great deal of cushion to satisfy any large gaps and will compress nicely to smaller ones.

BUT I've still found water on the floor on the passenger side. Doing some more investigation around the windshield, as M.B.DOC suggested, I've popped the fuse/relay cover on the passenger floor and checked up high and find the insulation towards the firewall is wet. Water is coming from above - now the questions remains...from where???

Any suggestions? Anyone have such an experience? Tks

[Autobahner]

I've found the culprit and thought I'd share as I've never hear this one before. The water leaking into my truck was as a result of the sunroof drain hose...no, was not clogged. The water was coming in the passenger front foot well. The front passenger sunroof drain hose comes from the sun roof down the A pillar and then snakes out the passenger compartment through a grommeted hole in the body side below the A pillar. Typically, water from rain drains down the sides of the lower right and left of the windshield (not only through the drain holes in the rain tray) and down the outside of the A pillars. Some of this water also drains into the inside of the fenders inside and behind the wheel well housing shielding. This water drips onto the area of the grommet from the sunroof drain. This water was seeping around this worn grommet going into the passenger compartment.

Mercedes had designed the external portion of the sunroof drain with a long 6" piece of tubing, this flaps up and down and has resulted in the grommet moving up and down slightly and therefore no longer creating a proper seal.

Remove the wheel well shielding and silicone around this grommet and it will solve the problem. Also you can shorten this pathetically long drain hose to a more reasonable 1-2" so it won't bounce and cause this wear. I did both sides - so far all it dry.

That will fix it! Lot's of money saved and a mystery solved with the cost of a tube of silicone. Would not want to know what the Mercedes stealership would want to replace the sunroof drain hose - is a bigger job than you think.