Windshield Wiper Arm Seal? - PeachParts Mercedes-Benz Forum

Cummmins · #1 07-31-2013, 10:51 AM

In my quest to make my car water tight, I have been making a lot of repairs and replacing seals. I noticed that if I run water directly on the driver side wiper arm where it goes into the cowl I get water leaking out of the HVAC box inside the car. I can only guess that the intake for the HVAC is below this area, and the plastic seal that goes around the wiper base is supposed to keep water out. In my case, the plastic "seal" as I am calling it is cracked in half. Does this sound correct? I also haven't been able to find this seal.

Gilly · #2 07-31-2013, 11:34 PM

Plugged plenum drain.

Cummmins · #3 08-01-2013, 10:46 AM

So, I should be able to remove that cover and see the drain? I just had my windshield replaced and that cover got glue to the gasket and I cant really get it out. I really don't want to get crazy with it and cause the new windshield gasket to leak....

JimFreeh · #4 08-01-2013, 11:50 AM

Pull the side carpets on each side of the console.

Look for deteriorated or missing drain lines from the HVAC plenum.

They drain on each side of the transmission.

Jim

Cummmins · #5 08-01-2013, 11:11 PM

I can only see a single drain in the center of the trans hump. I can see the water dripping from the front side of the HVAC box in the center of the hump. Will try to have another look tomorrow.

Gilly · #6 08-02-2013, 08:15 AM

The drain I am talking about are for rain water coming in at the base of the windshield, they should be higher up on the firewall, sometimes the holes get plugged with leaves and other crap from trees (acorns, helicopters, depends on what's around your house)

Cummmins · #7 08-02-2013, 05:11 PM

I checked the drains under the plastic covers on the outside of the car just below the windshield. They are clear. Are these the ones that you are referring to?

Gilly · #8 08-02-2013, 11:35 PM

Those are the ones I am referring to, yes. Jim could be correct too, but I normally think of these as being a problem when the AC is running.
I also am thinking they could be blocked at the hole in the plenum itself, have you tried running water in to the plenum and see if the water backs up? You would know right away by looking to see if water is coming out the drains. A lot of times you can tell if there might be a problem if you see lots of leaves and other crap in the plenum area, have seen it so bad that the leaves are decomposing and you have essentially a plenum full of dirt, and seeds are actually sprouting in there, the original "green" vehicle, LOL.

Cummmins · #9 08-25-2013, 05:29 PM

I am going to need some more help with this...

I have looked very closely with a flashlight and an mirror, and there is no drain in the HVAC intake tunnel between where air (and sometimes water) first enters the tunnel under the windshield, and the second flap which is directly above the fan motor. So, if I poor water into the intake of the HVAC tunnel it will flow to the first flap and get blocked for the most part. A small amount of water will slowly leak past the first flap, and then around the second flap where it is dammed up by the lip of the HVAC box which is directly above the squirrel cage when it is installed. It looks like about 1/2-3/4" of water would have pool up before it would finally flow over the lip and onto the blower motor where it could finally flow to a drain thru the firewall just down stream of that. I would assume that this drain is maybe for any condensation that may for from the a/c. Since the water gets dammed up in the intake tunnel it will eventually start leaking between the seam at the front/bottom of the tunnel, and down the front of the HVAC box, and drip on the on top of the trans tunnel and onto the floor. At first it appears that water is supposed to be sealed out of this center section where the air inlet is because there is a gasket on the top cover below the windshield, and the compartments on either side are sealed off with their own drains. BUT, below where the passenger side wiper arm is bolted down, is a drain that allows water to run right into the intake tunnel.

I am really lost on this one. Any help????

Cummmins · #10 08-29-2013, 04:26 PM

Bump...