Ben,
FIRST, remember not to over complicate.
The symptoms you describe are bad water circulation symptoms. Not Klima control symptoms. Not AC symptoms. In fact, the fact that your heat and defrost seem to be working is a vote in favor of it NOT being a Klima system-related issue.
Do the basics. Figure out why water is not circulating adequately in your cooling system.
When you did the valves, did you also do a citrus flush on the cooling system? If it's a 1979, you have had plenty of time for crud to build up, clog things, etc.
What about the thermostat? Is it the proper temperature? Is it opening (you can check it in a mug of boiling water)?
What is a "once over" in a radiator shop? Did that include a citrus bath, rodding out or some other means of ensuring that it isn't clogged after more than 30 years of use?
Worse thought: While the engine was opened up for work, did a rag get used to stop up a leaky water jacket port, but not pulled when you put things back together?
Get one of those cheap IR thermometers and point it around the engine. See if there is any part that it getting hotter. Maybe you can find an error.
You DID connect the radiator lines back correctly, not backward, didn't you?
Sometimes, air pockets can form in the system. There are archive posts about addressing this issue.
Best of luck with it,
Tom
In a message dated 9/27/2011 5:35:09 P.M. Pacific Daylight Time, bgiovan@cavtel.net writes:
Fired up the 300SD and cranked on the second try. Yay! Only took me 8 months to get it put back together.
Various nit pick issues which I can handle but one has me stumped. 1979 300SD (W116) with the lovely ACC/Chrysler Airtemp. If I run with the defrost on HIGH and heat on MAX, the car will hover around 100C. As soon as I turn off the defrost (because I'm boiling), the temp starts to climb. Then I chicken out, crank up the heat and it settles back to 100C.
History - bought the car from an old cat in Gainesville, FL back last December. Great shape but blown headgasket.
What I've done over the last 8+ months:
Professionally rebuilt head with all new innards
New 1985 Cam
Rebuilt starter
New water pump, new Meyle 7 blade plastic fan and clutch
Rebuilt vacuum pump
Rebuilt turbo
Sent radiator out to radiator shop for once-over.
Various "while I'm in there I might as well's"
Thoughts on the cooling issue? AC doesn't seem to want to engage from inside and being the dreaded Airtemp, not sure where to start.
Ben near Detroit
