Bemomods

Hello I am new to the forum and looking forward to learning and possibly helping here and there if my knowledge permits. My mother purchased a 1977 450SLC in 97 from a lawyer she worked for. He had it imported from Germany in the mid 80's. It is starting to have many issues but she cant afford to pay the mechanic that has always done work on it, so being retired now I have more time then money and like to work on cars.
I have a Haynes manual but I am currently looking for a more comprehensive manual. I am having trouble identifying a part of the cooling/heating system. The manual I have does not address what the part is. That may be because this vehicle was originally in Germany. To my understanding Mercedes had different specs for different regions for identical models.??
It is located on the firewall just behind the drivers side valve cover. it has a hose going into it that comes from the motor just below the intake manifold, I believe. It has a orange colored vacuum actuator attached to it by a white arm and that is where it is leaking coolant. I have included pictures. I would like to now first of all what it is called and what it does as well as a part number if possible. Sorry the pics are huge. I will try to down size them in the future.

ygmn

I think it is heater water temp valve.
Vacuum acuated by controls.

SO litle pot is vacumm actuator which will open and close valve for heater water to enter cabin...

AGAIN I THINK

Been a long time since I was working on these old MB in High school summer job.
Post more pics of outside.... great cars; anything with 450 in the name (450SL 450 SEL) from late seventies loved them...

Bemomods

ahh thank you. I will post more pics. She needs a bath and the paint is oxidized and a dent I am having a friends son, a body man who has worked on a few, work on that. She is in rough shape and runs but I found one fowled plug ( potentially very bad),... not sure how long that has been going on.
She has been sitting for some time and only driven on very short "around town" trips,... also not good! These cars where meant for the open road. My mom is elderly and probably only drive a couple more years so I would really like to fix her up so she can get some more enjoyment out of it.
Thank you

Bemomods

I am wondering,,, is it a temp valve or merely an Open- Close valve. does the heater need to know what temp the coolant is at in order to start flow into the core. Just spit balling here trying to learn... A tall order..lol
Thanks again!

ygmn

Been a long time... the vacuum line controls it and more then likley goes to the AC control unit inside... and well vacuum is not very good at Proportional control since you depend o nlocal atmospheric pressure.
probably it is an on/off valve.

Best bet is to see if you can find repair manual for that car.
They are not hard to work on as properly designed to be able to get your hands where they need to go...

but ya gotta know what is what etc.

To prevent having heat inside car you can either not let hot engine coolant into heater core... or not let the air hit the heater core.
Today most block the air with a damper door and do not have anything blocking coolant flow.