2002 Ranger. New Radiator. New thermostat. Car is not overheating. About 6 months ago I flushed the heater core, a whole bunch of junk came out and water ran clear

Now on heat, any setting, any airflow, it only ever blows cold air. Drove car for an hour, engine was at temp, cold air. Checked under hood, the intake hose to the heater core was pretty warm/hot, but got cooler the closer the tube got to the heater core. Exit hose coming from heater core was cool. the large coolant hose was quite hot

Do I need to flush heater core again?

 

Reflush it. And swap the two hoses attached to the firewall. The heater core is not directional... coolant can flow in either direction. Routinely swapping the hoses will help keep the core clean.

 

OK, I will reflush it this weekend. I still have all the hoses and attachments so simple to do.

 

Reflushed the heater core both ways, there was some sort of blockage in there, hose eventually got it out, heat works good now