Daniel: Thanks for the advice. I checked tonight and the fan is running. While it is running I can hear the condenser(?) kicking in and out and the car runs fine. The over-flow hose is connected properly. It blows a bunch of cold air! The engine temperature gauge does not rise any higher than usual (just under the mid-point)---in fact, when I saw the steam while driving through the Virginia mountains I kept my eyes on the temperature gauge and it never rose then either. Again, the water level in the reservoir is still at the full line---no change in 1500 miles of driving. My gut feeling is that when I stopped for gas after driving three hours in the mountains and heat, the car didn't have time to cool down?