I just bought an 87 240 4spd OD with 220,000 miles. Replaced main rad. hoses, belts, water pump, and radiator. The previous thermostat was punched out so maybe this is a problem that the previous owner tried to solve. The bottom of the radiator and bottom hose are slightly warm and the top hose is really hot after 15 minutes. The temp guage was sporatic until it quit all together but it showed the temp climbing into the red occasionally. Since the bottom hose is cooler than I think it should be I don't think it is the guage. I stuck a garden hose in the thermostat opening and backflushed and water came out where the bottom hose is. The heater works great. Why isn't the water circulating correctly? Any thoughts are greatly appreciated. Thanks!