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.
Any noises abnormal heard in the dash?
While idleing at operating temp are both heater core hoses on the firewall very hot?
ANy color concerns ever noticed in the coolant?
Since the coolant has beenn a nasty brown then this means there is a good chance or corrosion contamiantion and some blockage and water pump fin deterioration. I recommend a new water pump and a good flushing of the engine and radiator and heater core to prevent in future concerns from arising. As for the heater core hoses being hot then this means the core is hot. You are looking at a broken blend door or actuator or control head issue. You need to see if the blend door actuator operates when commanded in hand and see if you can manually turn the blend door to get heat.
Click here for blend door actuator removal