removal of the center console

Dude! If you idle for a long time in your driveway, will the heater blow hot? If yes, then your heater core is fine. When you start moving, does your heater get colder? More details please!

What year is your 300SD??? That will tell us your body #!

His is 82

makes no difference on speed or RPM . i can be driving down the road turn the key off then back on. it then blows hot once again.

i just want to see if something is moving servo wise and unless i find that bolt i can't do that..

also what color is the vacuum line that goes through the fire wall for the heat & AC.

AC works fine in the summer

the case, minus a few cans!

well unplugged the mono valve and now have heat,

guess i will be getting one tomorrow.

my right foot is so happy now!!!!!

the case, minus a few cans!

"Driving down the road and turn the key off..."? WHOA! Mine stops dead when the key is turned off. LOL! How do you manage this feat? (Rhetorical question).

the blower stops but the car keeps rolling was told the mono valve is going bad.

unplugged it and its warmer. am waiting for one next week!

the case, minus a few cans!

I have an '81 300D which does exactly the same thing...blows warm air for less than a minute then begins cooling down rapidly. It acts as if the hot water circulation pump works only at startup and then almost immediately shuts off. I can turn the climate control off and back on and the same thing occurs...warm air for 15-20 seconds, then cool air once again. Any serious suggestions?

Ahh... you got that dreaded servo... my suggestion is to clean all the contacts on that servo in the engine bay... make sure clean and good contact.

If you don't want to spend money for a rebuilt one, then you can build a contraption that bypass that servo and put a valve so you can control the amount of constant heat.

tiger your speaking of the water valve right?

the case, minus a few cans!

Those older one got those monster water valve... costing a whopping $300 for a rebuilt one... you might be able to get one for $200 or so...

They are not the simple dinky stuff we got... but durable!

Tiger, god i hope not 300.00

well i now have heat, REALLY!

the water valve had a rip in the gasket. i just pulled the little C clip off and removed the piston that the magnet pulls up and down. now it is open and the feet are happy along with every one else.

the water valve in my car has the 4 screws & the plug on the top.

the screws go into the plastic body of the valve & can be stripped so make sure every thing is lined up good first.

the auto still runs the fan properly so its not an open window event from to much heat.

i thought the valve could be rebuilt?

also what are the 2 small hoses for that stick out if the top of the fire wall they also have coolent in them as i had to remove the one on the pass side to get one of the screws out?

the case, minus a few cans!

What Tiger is referring to is to disconnect the water hose that comes from the engine where it goes into the servo. Install some type of shut-off valve at that point. Disconnect the hose that attaches to the servo and goes into the firewall and connect it to the other side of the shut-off valve. You just replace the servo with the shut-off, you just by-pass the servo unit. The water comes from the engine, through the shut-off valve, then into the heater. When it's cold outside, open the valve to allow water (hopefully hot) to flow through the heater. When it's hot outside, turn off the valve to keep water from flowing to the heater. You are now the cabin thermostat.

Larry In the back yard, under the oak.

hate to sound dumb but the electric valve & the servo are the same thing?

also i have the main inlet hose and 4 outlet hoses

2 small ones that feed the top of the fire wall & the others under the electric valve. i know the one to put the valve on comes from the front of the block by the water pump.

GOD i need to find a service manual

the case, minus a few cans!

His servo is not the same as our Monovalve Pool Man.

good ! maybe the mono valve is cheaper

the case, minus a few cans!