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.
We have heat in the car but when you change the speed of the blowe the heat is cooler