is it possible to unplug the heater core with a garden hose by back flushing under low pressure ?
heater core on 2002 Jeep Liberty
You can try to do it, but the garden hose may not be strong enough pressure. Yould could try.
It might work, if the cooling system is not to badly corroded, as if your coolant is very rusty and brown looking, then if this is the case, you will need to first flush the system and then replace the heater core.