Heater not working.

[Trap]

02 Explorer 4WD XLS
Looking for help with heater issues. Here's what I've checked so far;
Blend door working: ✔
Radiator full:✔
Heater valve operating: ✔
Hose going to heater core is HOT, hose coming back from heater core is cold... Should they both be hot? Mechanic friend said may need to flush the system, possible line stopped up somewhere?

Any help is greatly appreciated!

 

[fordysenior]

Possibly the thermostat is not working, needs replacement?

 

[Trap]

Possibly the thermostat is not working, needs replacement?

Temp is always around normal range, wouldn't I be experiencing overheating issues if it were the t-stat?

 

[BrooklynBay]

Maybe the heater core is clogged? Flush it with water & compressed air.