Water is leaking into my cabin... Any suggestions?

[Chris_c200]

Hey guys, whenever it rains, water is finding its way into my cabin on the left side of my c200 along the wall under my dash board. I have removed the window cowling and found thats all fine with no holes and also that the drain isnt blocked. Has anybody had this problem before? Ant suggestions would be much appreciated as this leak is behind a piece of electronic equipment and could easily interfere with that it says siemens on it.
Regards, Chris_c200

[OzC36]

Since you are in NZ we assume that you have a right hand drive (RHD) car. That would mean that on a RHD car that the ECU is on the left side, which is the same side that you have the water leak?

I wonder if the problems are inter-related. Are you sure it is a water leak from outside and not a coolant leak to the heater?

For example the following photo is a crappy piece of plastic that is prone to breaking and carries warm coolant to the car heat exchanger:

http://img227.imageshack.us/img227/6286/dsc03099kd1.th.jpg (http://img227.imageshack.us/my.php?image=dsc03099kd1.jpg)

For info, the following picture shows the left lower windscreen, the cabin air intake area and the cabin blower fan. You can just see the aft computer of two; the forward one is the ECU (I think). Any pooling of rainwater in this area or leakage through a damaged/perforated area has direct access to the cabin on the front left side:

http://img45.imageshack.us/img45/6752/dsc03091kx9.th.jpg (http://img45.imageshack.us/my.php?image=dsc03091kx9.jpg)

You owe me a beer!

[Chris_c200]

Hmmmm interesting.. thanks for that advice mate I really appreciate it. As for the beer.. lol ill just post it over to the Gold Coast.
So this morning right, I had a closer look and found the water was entering through a small rusted hole directly below the top bracket which which holds up the electronic device which says siemens on it. I used sealant and sealed this hole up.
Now the interesting thing is, I has a coolant leak and I have no idea where the leak is. About once a week I have to put in a litre of coolant. So you think this could be related?
Thanks for your help mate.

[OzC36]

The crappy piece of plastic I mentioned is positioned at the left rear of the engine block where the coolant hose connects through the firewall. It is very close to the engine oil filter on the C280/C36 and suffers mechanical distress from grease monkeys doing a filter change.

The part is easily availabe and very cheap which leads me to believe that it is a known and likely failure part. The crack is hard to see and coolant leak can be disguised or covered by the sound proofing material until it lets go big time!

The area that coolant migrates to and drips onto the ground (near the flywheel/bellhousing/auto transmission area) might lead you to think it is only condensate from the airconditioning.

Otherwise it might be that the heat exchanger for the heater is corroded or the connections loose. This would certainly make your floor wet under the carpet, and you might confuse that with rain leaking in (because when it rains,it is also cold and that's when you TURN THE HEATER ON). I think if you leave the heater turned off, there is no coolant circulation or pressure in the heat exchanger (thus no leaks). I might be wrong. Try it and see?

More photos:

http://img514.imageshack.us/img514/9738/dsc03087mb6.th.jpg (http://img514.imageshack.us/my.php?image=dsc03087mb6.jpg)

http://img440.imageshack.us/img440/6073/dsc03086ze3.th.jpg (http://img440.imageshack.us/my.php?image=dsc03086ze3.jpg)

Just above ECU, you will see the throttle cable. Below the throttle cable, sandwiched between the two firewalls at the bottom is the coolant hose leading from the plastic connection previously mentioned, to the heat exchanger. This area should be dry as a bone.

http://img240.imageshack.us/img240/8314/dsc03093ze4.th.jpg (http://img240.imageshack.us/my.php?image=dsc03093ze4.jpg)

[Fizzle]

Not Thread Jacking But I Have To Same Problem. But I Only Notice Water On My Front Passenger Side Floor When I Wash My Car Or There is HEAVY Rain. Almost Like Something Has To OverFlow To Allow The water To Get In. And When it Does it Is A Lot. But The Glove Box never get Wet. It all Ends Up On The Floor. I've Looked Under The Hood And Can't Seem To Find Any Cracks or Holes. So basically I Don't Think Its The Heater Thing that Was mention But i don't Know What It Is.

[Chris_c200]

Hey bro mine turned out to be a small rusted hole in the engine bay which was letting water in. Another thing for you to check would be whether or not the window cowling is blocked up. locate where it is leaking from in the cabin, then try and pinpoint the area its leaking from in the engine bay. Best of luck mate

[Green Lantern]

bump this thread, this is happening to my moms car and its annoying!!! car cant be driven when its going to rain or massive amounts of water comes into the cabin. this also means i have to go and pick her up in my car which is too low for NYC streets :(. anyone got a fix for this? if i spray water down into the drain next to the wiper, water gushes into the cabin like a waterfall.

[Green Lantern]

anyone have any advice?? its gnna be raining in NY for the rest of the week.

[Green Lantern]

i found that the leak is coming from where the red arrow is. i removed the blower and sprayed some water into the drain and water just gushed in. anyone know what is next to this?

http://i254.photobucket.com/albums/hh83/LiCelsior/blower6.jpg

[OzC36]

The intake in front of your windscreen is an "air/water duct" (item 20). It is designed to allow fresh air into the heating/ventilation system, but at the same time prevent water from also entering. It achieves this by draining water at the low points. If a drain(s) (central drain - item 10) (side drains - item 52/115) becomes blocked, the water in the duct will rise until it reaches the level of the air duct. It will then drain via "pipe socket" (item 5) into the blower motor housing (item 310) and exit into the front passenger foot-well area.

The drains typically get blocked by decaying vegetation (leaves etc) that fall into the intake. Don't park under trees!

http://www.detali.ru/cat/oem_mb2.asp?TP=1&F=202028&M=104.941&GA=722.328722.424722.604722.605722.629&GM=717.441&CT=F&cat=44V&SID=83&SGR=110&SGN=02

http://www.detali.ru/cat/oem_mb2.asp?TP=1&F=202028&M=104.941&GA=722.328722.424722.604722.605722.629&GM=717.441&CT=F&cat=44V&SID=83&SGR=045&SGN=01

[Green Lantern]

yep that was the problem, the drain was clogged and the water backed up so much that it went into the air vents. i cleaned it out today and boy was there ALOT of dirt.