Hello Customer'm Chris, a current Ford Lincoln Mercury employee.
Thanks for visiting Just Answer. I will do my very best to help you resolve your concerns.
thecoolant doesn't look the greatest
i recently changed the thermostat but that changed nothing
both heater hoses are hot but one is definately hotter than the other
the heat selector does work from cold to hot
the vehicle has about 100,000 miles
Your last reply leads me to 2 possible causes.
I suggest you remove the thermostat and upper and lower radiator hose and the heater core hoses from the engine. Now flush the heater core and engine and radiator forward and backward using your garden hose. Pay close attention to the flow rate on the heater core to see if there is restrictions. This will clean everything up. Now refill the system 50-50 and giv eit a shot, If this fails then replace the water pump. I really do not believe this a concern with the interior of the vehicle with the blend door or door actuator since you can control what temp you do have.