240d heater wont turn off
 

I have searched the forum and I cannot find anything on the heater on a '77 240d not completly shutting off. Any help would be appreciated. Its getting warm every other day in East Texas. Thanks,
Treeman:confused:

Can you not stop the blower motor or is just a matter of hot air drifting in?

Motor seems to be off, seem to be drifting in. But a pretty good drift.:sweatdrop

Your heater control (water) valve may be stuck open. Take a look -- it's just a little nickel/dime part.

Yeah - warm weather is quickly approaching - the added heating will be dreadful.

Too much heat = Bad Heater Control Valve
 

I agree with GermanStar that you have a stuck heater control valve, but it is not exactly a cheap item. I did a quick check and they run about $55. This happened to a 240D I had years ago and I installed a cheap manual valve in the circuit allowing me to shut down all water flow. All you need is a 1/2" 1/4 turn ball valve hose connections either on the valve or threaded into the end connections. Then just cut your heater supply hose and clamp in the valve. You will be able to shut off the water flow to the heater core that way. Should cost you about $8 and take about 30 minutes to install. The hose you want to cut is on the passenger side near the wheel well.

Do you have the 240D with the manual controls or the ACC with the Evil Vacuum servo...

It can be a cheap fix or a darned expensive one depending on which it is.

Well, cheap is relative. When you consider that most other w123s of that era have a heater valve that'll cost you around $500, $55 seems like a bargain. :D

Some 240Ds have the ACC so waiting for him co confirm for certain. If he's lucky its the manual that most have.

Yeah, I've seen it occasionally, but it's rare.

I have Manual Controls. Interior controls knobs attached to a wire that move the corresponding plastic arm it is connected too, on the heater control under the hood. What scares me is the fact that I have been catching wiffs of antifreeze. I read the post on breathing the Glycol and its got me a bit concerned.

I replaced the heater control valve. Still getting heat and the smell of anti-freeze. I guess I will have to replace heater core. For now I have bypassed the heater.If it could be something other than the need for a new core, I dont know. So if anyone reads this with another thought before I try my hand at a core removal. PLEASE CHIME IN!!!
Thanks,
TREEMAN