How do I flush the heater core
if i’m mistaken you will have to flush the whole system. get some cleane at the auto store, for the cooling system, and i belive you need the heater to be on high, and hot as it gets.
Most service stations will do a “reverse flush” by attaching the flushing hose to the heater outlet hose (with a “flushing T”) and pushing the water through the heater core and the rest of the system to exit at the top of the rad with the cap removed. I used to do this until it became illegal to drain antifreeze on your driveway.
If you go to your auto supply store and ask for a “flushing kit” you will get all the parts with the instructions.
Good luck!
We have heat in the car but when you change the speed of the blowe the heat is cooler