W-116.......Condensation Riddle
 

Hey Gang - i have a problem with my '79 300SD air conditioning. I have had the car for 2 years and all of the sudden, there is condensate from my AC unit building up in the rear passenger seat under the carpet. I know it's not coming from outside, cuz it happened after a week of no rain. i have looked at all the obvious drain tubes in the engine compartment and they are working fine. Any experiences or recommendations that might help me identify root cause?

Thanks - JB

The evaporator box should have two drains going from the box to the transmission tunnel area. These go bad with time. You'll need to pull the side carpet on the console to see them.

I've had success replacing them with red 3/4" heater hose in our W124.

Jim
Jim

Unfortunately, the drains aren't accessible from the engine compartment. You have to crawl underneath and look for them around the transmission. There should be 4 drains. I had good luck with shoving a coat hanger up and slowly working all the gunk out...

HTH!

1980 300SD
I am also having this problem i have cleared out the 2 draind i can see, i still have the paneles removed from under the dash, if i take a sharp turn i get water on my foot, i need to find the other 2 drain holes yall are talking about. i was told to use compresed air and blow the gunk out from the tube in the transmission tunnel area. i am not having to much luck, also i thought i might try some simple green or something in the drain to clean any mold that might be growing. i am geting frustrated with this. i do not wont any more water in my car. :(

I've had the water on my foot thing before... not pleasant when the water is cold and you're wearing flip-flops! Just get under the car and poke around for a while. Thats how I found mine! I can't remember any details to help you find them though... its been a few years since I cleared mine out.

Thanks guys. You have given me some leads to follow. I'll let you know how I fare when I have a chance to get dirty.

JB

There are 4 drains. I gain access to them by removing the under dash panels on both sides of the center console.

The flexible hoses that go from the drains through the firewall become clogged with gunk and can be slipped off for cleaning. You will also want check the drains where the hoses attach as these can also be clogged. I cleaned mine by blowing compressed air back through them.