I have a 2013 legacy 2.5. The heat stopped working on it. The blower tuns at all speeds, i checked (and filled) the overflow, added coolant to the radiator and still no heat. I burped the system with a filling funnel to get the air out, no heat. Both inlet/outlet hoses on the heater core get hot. I pulled the hoses off the heater core and flushed it/reverse flush about 6 times with just a bit of black scale and granular stuff ending up in the bottom of the bucket each time, refilled the core with coolant, reattached the hoses and burped the system again, no heat. I am leaning away from it being the thermostat because even after a long drive I still don’t get any temp change in the vents. The settings all work moving from defroster through the system blowing at your feet. I’m just not getting any heat out of the vents. Any ideas or additional diagnostics I can do would be greatly appreciated, TIA!