Heater problem
1999 Mercury Sable 6 cyl Front Wheel Drive Automatic 96,580 miles

my 1999 sable is not putting out very much heat. At +25 degree's it can barely defrost the windshield, i put a new 195 degree thermostat in yesterday and that didn't help. I flushed the cooling system out a couple of times and even reverse flushed the heater core a couple of times. Do you think the heater core might need to be changed. Jim D

Sounds like the heater blend door actuator dorman part number 604-206. Otherwise something is blocking the door itself. Let me know what you find.