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'83 240D, '86 420SEL
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Discussion Starter #1
I have a problem with my E320 wagon. When it is raining (and even after) the windows fog up excessively. Defrost does not work quickly enough, partly because my A/C isn't working. My impression is that the cowl drains are at least partly clogged and just contribute more moisture to the interior. Has anyone had this problem and can tell me where the drains are located?
 

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04 odyssey (265k) 1995 E320 wagon (295k)
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With hood open, look in corners where windshield and fender meet. There will be a black plastic section that looks like a funnel. They can get clogged with leaves and debris. If you pour water down the plastic funnel looking section, it should just dump on ground. If not the drains are clogged. You can clean with something flexible, but semi rigid. String Trimmer line is a good one that wont do damage that a coat hanger might.
 

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'83 240D, '86 420SEL
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Discussion Starter #3
I have a problem with my E320 wagon. When it is raining (and even after) the windows fog up excessively. Defrost does not work quickly enough, partly because my A/C isn't working. My impression is that the cowl drains are at least partly clogged and just contribute more moisture to the interior. Has anyone had this problem and can tell me where the drains are located?
I should have mentioned, the wagon is a W124. I also have a W123 '77 280E and the W123 '83 240D and no longer have the W126
 

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W124
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Don't overlook that the stationary rear windows are a prime leak point in the 124TE. Yes you should clean the drains to rule them out but a rear window leak can fog the entire interior.
 

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'83 240D, '86 420SEL
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Discussion Starter #5
With hood open, look in corners where windshield and fender meet. There will be a black plastic section that looks like a funnel. They can get clogged with leaves and debris. If you pour water down the plastic funnel looking section, it should just dump on ground. If not the drains are clogged. You can clean with something flexible, but semi rigid. String Trimmer line is a good one that wont do damage that a coat hanger might.
Thanks for the reply. I looked at the corners and saw what look like drain lines about 1/2" diam. but could barely reach them. Are you suggesting pouring water in the air intake in front of the windshield, If that is clogged, where would you get access to the tubing to clean it with the trimmer line?
 

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'83 240D, '86 420SEL
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Discussion Starter #6
Don't overlook that the stationary rear windows are a prime leak point in the 124TE. Yes you should clean the drains to rule them out but a rear window leak can fog the entire interior.
Thanks for the reply. I haven't really seen evidence of water in the car. The fogging seems to be tied in to the fan operating as if it is pulling moisture out of the plenum. To compound the problem the A/C isn't working and neither is the rear window defroster.
 

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'95 E300 DIESEL, '91 600SEL, '92 600SEL
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Without fully functioning A/C, it is going to be next to impossible to prevent fogging
 

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04 odyssey (265k) 1995 E320 wagon (295k)
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Yep just pour water right in that little " pipe"
Agree with sbaert, without a/c to dry the air it's very difficult to defrost. So marginal ac can cause the symptoms you describe.
 

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W124
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Thanks for the reply. I haven't really seen evidence of water in the car. The fogging seems to be tied in to the fan operating as if it is pulling moisture out of the plenum. To compound the problem the A/C isn't working and neither is the rear window defroster.
My bad; misunderstood your post. If you have this going on WHILE its raining, yes, as others have said, fix your A/C.
 

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'83 240D, '86 420SEL
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Discussion Starter #10
My bad; misunderstood your post. If you have this going on WHILE its raining, yes, as others have said, fix your A/C.
It happens during rain but afterwards as well. My '77 280E doesn't do the same thing and, without A/C the defroster works to take care of any fogging. In the wagon, the defrost cycle seems to add to the problem. I want to fix the A/C but my mechanic has determined that the freon leak is in the evaporator coil. To replace it requires complete removal of the dashboard including steering wheel, console etc. We tried sealant as a last resort and it worked for a few months. I still don't know where to get access to the drain tubes to clean them out. It is a great car but it can get dangerous to drive in wet weather.
 

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'95 E300 DIESEL, '91 600SEL, '92 600SEL
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The defrost function is useless without a proper operating A/C. Defrost works by removing moisture inside the cabin. Not possible to do without A/C.

Yes, all W124 were blessed with defetive evaporators, and the only permanent fix is to replace them. Adding sealant is snake juice and usually does more than good.

No real A/C mechanic will ever advocate using such sealants in the same manner as there is no such thing as headgasket sealer in a can.
 

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'83 240D, '86 420SEL
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Discussion Starter #12
The defrost function is useless without a proper operating A/C. Defrost works by removing moisture inside the cabin. Not possible to do without A/C.

Yes, all W124 were blessed with defetive evaporators, and the only permanent fix is to replace them. Adding sealant is snake juice and usually does more than good.

No real A/C mechanic will ever advocate using such sealants in the same manner as there is no such thing as headgasket sealer in a can.
Actually the defrost cycle even without A/C works by raising the glass temperature above the dew point. That is what was done before cars even had A/C. (I'm old enough to remember those days). Sealant is a last resort on the A/C since removing and replacing the entire dashboard would cost more than the car is worth. It did work for a while.
 

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'92 300TE 4matic 280,000miles, '92 300TE 4Matic 'Ice Blue Metalic' 101,000miles
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My AC doesn't work and I don't have fog problems with the windows that the HVAC system can't handle. But I live in a semi-arid climate....maybe if I lived in Seattle where the car came from it might be different.

There are a couple of rubber drains inside the compartment where your fan blower is.....make sure they're not clogged or rotted away.

Kevin
 

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W124
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A roll of paper towel in the car does a pretty good job of clearing moisture from the glass.

How did your mechanic test the evaporator for leaks? Did he Isolate it from the system and do some type of leak test without any other devices connected?
 

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1993 300CE Cabriolet (mine) ; 1994 E320 Wagon (wife's) ; 1990 Benz 300E 2.6 (son's)
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I still don't know where to get access to the drain tubes to clean them out.
the drain tubes are directly under those square 'funnels' under the very back corners of the hood... just run the string trimmer cord, or whatever else (I've used bicycle brake cables before) straight down the 'funnel', and use low flow of water from a garden hose to help wash stuff through while you run the string up and down, using enough string to reach the ground...
 

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1989 W124 260E
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Why do cars with aircon get this,, and cars without aircon dont ? I have no aircon and i dont have condensation in mine and she sits out side in all weathers,,.all my vents are clear i see to that .
 

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'95 E300 DIESEL, '91 600SEL, '92 600SEL
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^This and remember that besides the standard drainage spots for the roof and windshield located underneath the hood, the A/C cars have dedicated evaporator drain tubes located at each side of the transmission tunnel.

If the evap drain tubes get clogged or restricted it can cause water buildup inside the blower box. Also common is the evaporator tubes disintegrating due to age letting watter build up underneath the floor mats.

Any car will fog up under the right conditions, such as driving without A/C on cold humid days or staying inside the car for several minutes after turning off the engine.

Personally, a car without A/C is pretty much worthless to me. The main reason being that I cannot support a draught from a cracked or open window without catching a cold. A tilted sunroof is about all I will tolerate if need to be. Otherwise, windows and sunroof always stay closed.

And in the other half of the year, you pretty much wish you had A/C.
 
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