My heat cools quickly once the blower fan is turned on. I can shut off the system for 3-4 minutes and will have heat for less than a minute once fan is again turned on. Replacing the thermostat and performing two radiator flushes has not improved the situation. Before I pay our local Ford dealer his estimated $472.00 labor PLUS parts to replace the heater core, can there be other components causing this? I am thinking that the core is virtually clogged and since the hot coolant is only seeping through the coils, the blower fan is forcing the heated air away faster than hot coolant can move along the core's tubing. Please give me your ideas. How can I perform a more thorough flush of the heater core shy of removing it (which entails the entire dash assy.) when the standard radiator flushes did nothing to improve flow through the dash? Help.....it's already cold here in southwest VA!
Many thanks!
im1believer

 

It's your heater core, before you flushed coolant the first time was the coolant original? You can try to remove the heater hose from water outlet and back flush the heater core, but chances are that the component is just junk.