Right rear passenger floor panel is SOAKED with rainwater! - PeachParts Mercedes-Benz Forum

86560SEL · #1 12-11-2005, 03:15 PM

I did some investigating today to see why my rear window was fogging over at night. I checked all of the floors and they are bone dry, except for the outside part of the rear passenger floor, which is sopping wet! I could see water standing on the carpeting. I lifted it up and there is a puddle of water under there. Luckily, there is NO rust and it still looks new under there, but not for long if this keeps up. I want to get it fixed ASAP.

Is is possible that the door seal is leaking, or perhaps the sunroof/drains are stopped up? The door seal appears to be a bit "flat" about 1/2 way down on the front part of the door. If it was the sunroof leaking, would it get in this area? Also, about the drains- where are they located? How do I check them to be sure they are not clogged? Also, the trunk seal looks fine, but I have condensation inside the trunk lid. Also, that "lip" toward the front of the trunk, below where the rear window is, is also wet. Possibly it is just my rear window seal leaking causing this? I really need to take the hose to it, but it is too cold today. It is only in the upper 30s- well below normal. BRRRRR.

BTW- it is a 85' S-Class sedan, so the 81-85 models would be the same. Thanks!

Thanks in advance!

t walgamuth · #2 12-11-2005, 04:14 PM

seal would def let water in the trunk. i would clean it really well and caulk with black silicone between the glass and rubber. i dont know where the sunroof drain goes but it could be that. also if the drain is plugged it could be running over the gutter. if that it would show on the headliner.

the door seal seems unlikely, but possible.

good luck

tom w

Hatterasguy · #3 12-11-2005, 08:16 PM

Ahh yes W126 water leak's are fun to track down. You really need to just spray the car and poke around. It could be your door seal or even the window seal. The sunroof is easy to inspect, just make sure the drains are clear. If they are clear it won't leak. Their are two drains in the front corners of the sunroof, I usually shoot compressed air down them. I guess you could also shoot some water down them.

As for the trunk their are a couple common spots:
The antenne seal, if its hard just replace it. It costs $2 so don't mess with it.
The rear light seals also will leak and weep down into the wells, making it look like something else is leaking.

86560SEL · #4 12-11-2005, 09:26 PM

Thanks for the replies. If it ever warms back up, I will try that hosing down. It is really bugging me that there is water in that floorboard.

I looked at the sunroof and there appears to be no water on the headliner area. I have never even opened the sunroof. Almost afraid to, because I do not even know if it will close back. The seal around it is cracked a bit. I am guessing that even if the seal is cracked, if the drains are clear, then it would still not leak inside of the car? Stopping the leak inside the car is my #1 concern, then I will get to the trunk leak. I do not want my floor to start rusting. I HATE rust. So far, it is still like new, but water covered.

I checked the trunk and I cannot find any water in there except for the inside of the trunk lid and that "cowl" area inside the upper trunk, below the rear window area. I checked that window seal and it is still somewhat soft and pliable and it is 36* outside. I have not messed around with it enough yet to figure out to see if the inside of the rear 1/4 panels are wet or not. From what I can tell, the rest of the trunk is dry.

Leaks are nothing new to me. I am used to it. I was just hoping this car would be an exception. Its funny, but most every car I have owned has had a trunk leak. Most all of the 80s Japanese cars I ever owned have had leaks, but no 90s Japanese cars I have ever owned have had leaks. I have even had 90s American cars with trunk leaks. I had a 92' Buick with a MAJOR trunk leak. I had two cracked taillamps and water came in through them. Before I sold the car, I was checking the trunk and in the spare tire well, there was a foot of water.

If it is indeed the window seal on this Benz, can an auto glass shop simply re-seal the window if I did not want to go the "black caulking" route? I had a 72' Buick a few years ago that had a rear window leak and I had it removed and resealed at Safelite auto glass for $50 about 4 years ago. However, it seems this Mercedes has a rubber seal around the glass, rather than the conventional "glass laying on the seal", like most other older cars of this vintage have. Can I just buy a seal and have them install it if it is the seal causing it? Am I also correct that these cars have laminated rear windows, as opposed to the tempered glass like most other cars have?

I will check that antenna area to see if that is where it is coming in at. I guess I will check the light seals as well. Can any of these parts be bought online? The car seemed fine until we had that severe rain storm that night.

Thanks

420 SE · #5 12-11-2005, 11:12 PM

Is your water on the side with the non-operational window??

Are you sure that the window is fully up?? Even a small amount down if the storm was bad enough will let water in.

We have tropical storms so I know what 'fat' rain looks like!!

86560SEL · #6 12-11-2005, 11:17 PM

Yeah, that window works. I will double check it to be sure it is up. I think it is. I do not recall the seat being wet. I really do not think it is the door seal now that I think about it, because I do not see how that much water could even get in there. I think it is something to do with the sunroof or something. I HATE sunroofs. I wish this one did not even have it. My old 90' Lexus LS400 had a sunroof, and I think I only opened it about 7 or 8 times the entire time I owned it.

The only puzzling thing is that the headliner is dry, unless it is dripping down the "B" pillar or something into that floor. I guess I will try to open the roof and see if the drains are clogged, or permanately seal the sunroof with caulking.

I do not even know if it works or not, or even where the button to open it is. I think it is the button by the upper left of the heat/AC controls.

Thanks for the tip. I may go out now to look.

420 SE · #7 12-11-2005, 11:52 PM

The switch for the sunroof should be up in the front interior light. Pull back - open, push forward - close, push button in - raise, pull button down - lower.

If the power or switch fails you can operate it using a spark plug wrench via a little plastic flap on the left in the boot.

Cheers

86560SEL · #8 12-11-2005, 11:58 PM

OK. Thanks!

Anyway- I checked the window and it is closed tightly. However, I noticed that on that door seal, on the front part of the rear door, about 1/2 way down, there is a spot of surface rust around it. I bet it is leaking in there. I am going to check that spot.

If it is that seal, does anyone know of a good place to buy this door seal and is it easy to remove/install?

I want to repair that rust spot anyway. This is the only speck of rust that I have been able to find on the entire car. I think I have heard this is a common place for rust on these cars. Luckily, it is only surface rust @ this point in time.

haasman · #9 12-12-2005, 02:45 AM

It is common for this age of car to have hard and often brittle front and rear window moldings. I had a similiar problem with a 123 model. I was convinced it was coming from the doors/windows etc.

It turned out to be a leaking from window seal. The water would dribble down, make its way to the rear passenger well via acceleration. I change the front windshield molding and all was well once again.

If the windshiled molding doesn't snap back when pulled up, it needs replacing.

Haasman

Rob Pruijt · #10 12-12-2005, 04:38 AM

The drains from the air entry bay (between firewall and false firewall) can be blocked. Water will then be accumulated in this bay and trough the mysterious ways of gravity and air ducts end up on the rear passenger side floor.
Remove wipers and cover and see if there is any water in the bay. Clean it out, clean the drains with an piece of wire and a lot of water.

Hatterasguy · #11 12-12-2005, 10:05 AM

Did you pull up the carpet in the trunk and take a peak underneath? Remove the back of the tail lights and pull up the carpet and look around.

Water on the trunk lid could just be condinsation, leave the trunk lid open on nice days and let it dry out. I had to replace every seal back their and finally mine is perfectly dry.

As for the other leak. It may be the sunroof but I don't think so, you need to open it and check the drains. The sunroof seal is just for wind noise, it may keep a little water out but even if it was gone the sunroof shouldn't leak.

It could be the door seal 20 year old door seals are not going to be perfect.

If you do replace the door seal don't waste your money on the cheap aftermarket seals. They are absolute junk, buy an OE seal.

Fourings · #12 12-12-2005, 10:34 AM

When I was a VW tech in Seattle this was a constant problem, especially with the A2 chassis cars. The vapor barrier, which is the plastic sheet between the interior door panel and the door itself would get a hole, or start to peel away from the door and allow rainwater to fill up the floor with water. I don't know the 126 well enough to know if this is a problem with these cars, but if nothing else works....
It also did a good job of turning the bottom part of the interior door panel to mush.

86560SEL · #13 12-13-2005, 12:00 AM

Thanks guys for the additional replies. It is supposed to be sunny and warmer here tomorrow, so I am going to do some investigating.

I found a door seal for $89.00. I will call the dealer tomorrow and see what they have them for. Also, will take a quick trip to the car wash and soak the car down to see if I can find anything like that. It not, I will drag out the garden hose and check it that way.

Hatterasguy · #14 12-13-2005, 12:48 PM

An OE door seal should be about $100+/-. Use 3M weatherstrip adhesive to stick the new seal on.

Take your time and let everything dry before you close the door. Remember it is going to be a bit tight for awhile until the new seal wears in.