Today, I developed a leak (appears to be water) from under the dash. It is cold and evaporates so appears to be water. Also, it seems to stop when I turn off the air conditioner.

The car is a 1980 300sd with 200,100 miles.

What would be the likely source and is it expensive to repair?

Thanks

PS: Would have searched site for this but could not figure out how to word it.

Plugged up evaporator drain line.

Never messed with one so I have no idea where to tell you to look.

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'84 300CD Turbo 132k (Anthracite Grey) - WVO - My daily driver - Recently named coo-coo-coupe by my daughter.
'84 300D Turbo 240k (Anthracite Grey) - Garage Queen
'83 300D Turbo 220k (Orient Red) - WVO - Wifes daily driver

I'm not a certified mechanic, but I did stay at a HolidayInn Express last night.

There are four drain holes with rubber spouts. There are two on each side that are suppose to drain onto the top of the transmission. As these cars age, the evaporator ends which are steel, rusts and flakes off plugging the holes.

Take the under dash cover off both sides and the door vent duct. You can see with a light, the holes which are most likely plugged with rust. I take a coat hanger and bend it to poke into the holes.

The rust can hang into the rubber tubes so they have to be cleaned as well.

Plan on doing this about once a year. I have had too so far. I plan on pulling the evaporator at some point cleaning it and painting the ends with POR-15 to eliminate this from happening.

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1980 300SD Manganese Brown Metallic Clearcoat 248k
1979 300SD White 148 k
1984 300D Silver project car for daughter
1982 300D wrecked
1980 300SD 310K not running

Hopefully this link will work. It even has pictures.


I've sprung a leak, evaporator drain hose...

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Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John

The link posted above is helpful for 123 cars. However the 80 300SD is different.

Glad I read that link as I am rebuilding interior of an 84 300D and wondered what I did with the "hose" for the drain. So I guess it is not a hose but foam on the 123 cars?

I will try the trick with the oil bottle.

__________________
1980 300SD Manganese Brown Metallic Clearcoat 248k
1979 300SD White 148 k
1984 300D Silver project car for daughter
1982 300D wrecked
1980 300SD 310K not running

Looks like this will be my project for the weekend. The pictures do help a lot. Thanks for the help