I have been a little confused by the terminology regarding the ac/heater system in my 80 300D so I took some pictures in hopes of getting some more help fixing the problem. Does any of this look notoriously familiar to anyone and does anyone happen to have a good place for me to start so I can get the heater working.

http://i103.photobucket.com/albums/m.../fall08085.jpg
This is in front of the passenger side firewall in the engine compartment. Could this be the root of my problem at this valve??

http://i103.photobucket.com/albums/m.../fall08086.jpg
Or is it more likely that it would be the servo? Is this even what they call the servo??

http://i103.photobucket.com/albums/m.../fall08084.jpg
Or what about this mess on the driver's side in front of the firewall. Cut hoses don't seem to be good...

http://i103.photobucket.com/albums/m.../fall08083.jpg
Another picture of the mess with my hand propping up some of the cut hoses

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here are a few pics of my cars ac climate control monovalve. One pic is my present one in the car, which is just behind the valve cover, next to the battery. Another pic is of an extra housing, and the third is of the old 'guts' of the monovalve, which is what I ordered for $35 bucks from ********. You can see the split rubber diaphragm in that picture. I can't remember what the cost of the whole housing and innards is, but it's a 50 cent piece of rubber that screws up the whole show. If this is your problem, it takes about 1 minute to unplug the electrical connector, remove the two retaining screws and pull out and insert the new insides, which is about 3" long (the part in my hand). This may not be your problem. But I didn't see anything in your pics that looked like this. Mine is an 81 300D. I'm kind of puzzled. Even my daughters 82 240 didn't really look like your pics.??? Got any of the whole firewall, not so close?

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"Knowing is not enough, we must apply.
Willing is not enough, we must do." Goethe

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1951 Chevy 3100

2003 Indian Chief Roadmaster

1983 GMC 1 ton Dually

1982 Chevy 1 ton Dually, service body (sold)

'90 GMC Suburban 6.2 "SS Veg-Burban"
(single tank WVO\diesel conversion) SOLD

'81 300D ~ Mama's car...my job (now my car)(but still my job) SOLD

'83 300sd ~ rescue car SOLD

2005 Ford Taurus (Mama's new car)(NOT my job!)

The second pic is indeed the "EVIL" servo. Some members here have bypassed it with regular plumbing valves and just operate the heat manually when heating season comes. Servos can run $1000+ . To the left of the servo in that pic is the auxillary water pump. Might want to test that out too. I can hear mine running with the key in the #2 position and the heat on.

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'83 300D 198,000mi Howard
'03 Saturn Vue CVT 75,000mi(wifeys)

The last pic looks like the check valve to the door locks, do they work? A common removal. There's a vac leak in the door system somewhere, and the car won't shut off with the key.
But that has nothing to do with the lack of heat. You have the dreaded servo heating system, good luck.

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83 SD

84 CD

If I bypass the servo... what functions do I lose?? I guess I don't fully understand what the servo is supposed to control.

Your first picture is my first picture but they are different set-ups... I don't know if mine has the same type of insert or what but I'm bound to figure this out. I have a friend at a shop that I'm going to ask sometime this week or next weekend. In the meantime I'm going to continue to scour the info here.

I have an '81, which has the monovalve not servovalve, but if it were my car I would still bypass the servovalve and aux pump.

All you really need in the heater plumbing is:

- Hose coming off water pump (the supply), route to 1 of the fittings on the firewall going into the heater core. Patch in a cheap 1/2" or 3/4" manual plumbing valve so you can turn the heat off next summer.

- Hose going from the other heater core fitting on the firewall back to the engine.

- The fan has to work. I also put my fan on a manual switch, but this may take some screwing around to make it work independently of the servovalve.

That's how I've had mine rigged for over a year now, and the heat works great and is super easy to troubleshoot. I know the aux pump was intended to give better coolant flow at idle, but I haven't noticed any shortage of heat when idling.

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'81 300CD - 180K, cannot be killed by any conventional means
'99 Ford Escort - good MPG

Thanks, I'm beginning to think that this may be the best thing to do. I've actually been reading up on a post about how to do this. How long would you say it took you to do the bypass procedure? and describe for me what features I will lose by doing so??

It took me about 1 hour, and that's with tie-wrapping the hoses neatly so they're not vibrating around.

By the way I didn't even go to the auto store for anything. I bought a brass (or maybe it's bronze) water valve, brass hose-barb fittings, hose clamps and heater hose at Home Depot.

What you're giving up is fine control over the temperature, but with my car I need max heat pretty much all winter anyway. If it gets too hot I can always crack a window open a bit.

Does your fan work? If your fan blows air then the hose bypass should give you heat.

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'81 300CD - 180K, cannot be killed by any conventional means
'99 Ford Escort - good MPG

3/4 PEX valves fit the heater hose real nice...

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1984 123.193 372,xxx miles, room for Seven.

1999 Dodge Durango Cummins 4BTAA 47RE 5k lb 4x4 getting 25+mpgs, room for Seven.

Thanks guys! I'm trouble-shooting the system currently and might end up just doing the little fix described here.

Thanks again, I'll keep you posted