Drained down the antifreeze and pulled the thermostat cover today. Pucker factor went down considerably when I saw the O ring flopping loose on the old thermostat. Carried it into the house and demonstrated my Mr. Wizard skills to my youngest son with a pan of hot water and the old thermostat. Used time for economics and faith lesson as well. (Praying that it was $6.00 thermostat instead of $600.00 up sleeve job). Held our breath as candy thermometer slid inexorably towards boiling point with no sign of moving. Now teaching patience as we wait for eldest son to return from parts run. Thanks to all