I just climed out from under the Rattlemobile, after a rewarding--and inexpensive--day of wrenching.

After rebuilding the monovalve, replacing the aux coolant pump and ACC controller, I finally got the heater to work by power flushing the entire system. At high pressure (of course not too high) I blasted out another handfull of sandy, rusty, decomposed hose chunks, and grey goo.

Proceeded to do the de-oil flush with detergent. Rinse. Fill. Rinse.

Added citric acid solution, drove across town to pick up some anti-freeze. Dumped. Filled. Dumped. Filled. and so on...

Added new coolant, and now the heater will melt your face off. Operating temperature is five degrees cooler now, and the passenger cabin is thirty degrees warmer.

Thanks to all who contributed to this thread. Without your help, I'd be forced to drive a Yugo.

RSCarey