:EDIT: EVAPORATOR DRAINS: Cruising to work today in my 83 300SD on a typical hot swampy south Florida morning. Made a U-Turn to get to my work and I could hear what sounded like water splashing on carpet. I looked to my right and a waterfall had opened up under the dash on the passenger side! Water was gushing out of the passenger foot vent! Got into my work parking lot, muttering and cursing under my breath as I walked to my desk. Went out at lunch to have a look see. Passenger front floor, rear floor and driver rear floor are all soaked. Pulled the passenger front carpet, pulled the panel that covers the transmission hump expecting to find a nonexistent, turned to dust drain line or something. First I saw that the drain line is different on the SD than other models that have a foam drain line. The SD's is rubber and it is easy to access. It was in perfect condition. Looking at the orientation and location of the drain, it was impossible to cause water to come out of the passenger foot vent if it were leaking. I made the observation that the outside of all of the black plastic that encompasses the air conditioning evaporator and air ducting was dripping with condensation. I pulled the drain line and shot a flashlight up it. I could see something up there...maybe some leaves. Stuck a screwdriver up there and gave it some good roto-rooter action. Water started pouring out of the drain.....all over the floor pan.... Along with the water was quite a bit of rusty metal. The drain was blocked with rusty metal bits and fine bits.

Sooooo, questions of the day are....

1) What would cause rusty metal bits in the evaporator housing area to the extent of clogging the drains

2) Is there a drain on the drivers side of the transmission hump that is clogged as well or is there only one drain the the passenger side that I just cleaned.

FYI, if you ever have a waterfall coming from under the dash with the ac on for a length of time.....you have clogged evaporator drains....

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1983 300SD.....169,000 miles but quit counting a few owners and unknown years ago!