Can anyone tell me what part of the cooling system this is. It's on the firewall, 85 300TD. I obviously need to replace it.
Thanks

Attached Thumbnails

 

__________________
1981 300TD
1985 300TD

Missing monovalve, which controls the heat by cycling it on/off.

__________________
85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

You mean what part that isn't -



Sixto
87 300D

Okay, so heres the deal.
I am almost sure the mono valve has never been there in my ownership. That bracket on the firewall looks like nothing has been mounted to it for some time.

What happened is I went to warm my car up the other morning for ten minutes or so. Looked out and it was overheating, with coolant all over the engine bay. When it got warm enough outside to look at it, this is what I saw.
Is it possible the PO put something between those two hoses in place of the monovalve? I am stranded without a car right now. Could I just tie these hoses together and run the car without the monovalve for the interim?

__________________
1981 300TD
1985 300TD

You sure can. But you might need to keep the windows open.

__________________
When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl.

x2. Bridging the hoses means full cabin heat all the time. Might be a good idea in Maine.

Sixto
87 300D

Well I sure could use the heat here now anyway. Thanks
But I am still a bit confused. If you look at my picture, you can see the bracket, an electrical connection, and then the fitting with coolant in it and the hoses leading to it. I don't think I ever had a monovalve here... What do others think?

__________________
1981 300TD
1985 300TD

My money says that the car left Stuttgart with a monovalve. What may have happened to it in the years since is another story.

__________________
When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl.

Ah yes, I guess I didn't mean 'Never'
I meant since I've owned it... I mean it's not like it just fell off the other morning, right? And what does anyone guess the fitting between those two hoses is. It looks like the hose broke off one side, and maybe there was a cover on it originally, but what is that. Is it part of a monovalve, but missing the rest??

__________________
1981 300TD
1985 300TD

I would guess that at some point, someone installed a manual flow control valve in place of the mono valve and it has failed.

__________________
'83 300D, 126K miles.

Hard to tell from your pic but it looks like the hoses to the monovalve is blocked off. What is that thing with green coolant (wrong coolant btw)? Is it connected to the hose?

__________________
85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

I know the green stuff is evil. I was desperate a couple weeks ago to up my fluid to water ratio when it got down to the single digits, and I couldn't find any Zerex. The car came to me with mostly water in the coolant, and I foolishly did not do a winterizing check to that system.

That weird thing with the green coolant is what I am wondering about. The hoses pictured go into both sides of it (connection on closer side has broken off) but then the whole 'face' of that plastic thing is missing. And it doesn't connect to anything.

__________________
1981 300TD
1985 300TD

It's not evil. It's just not as good as the preferred option.

__________________
When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl.

That thing is probably someones attempt at a manual valve. I hope it was not driven with it broken. If you don't want to spend the money on a monovavle and the special hose, splice the pipes with a hose and get constant heat. Crimp it with a vise grip for summer.

__________________
85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

It does look like it could be the remnants of a generic cable-controlled heater valve.

http://www.bing.com/images/search?q=cable+controlled+heater+valve&FORM=HDRSC2#view=detail&id=D7163B1A082E90A2942F7DF01EEBC571D0A60C9C&selectedIndex=121

__________________
When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl.