water circulation question

back to the subject of flushing... Water flows through the heater core in one direction. Crap collects in there, sticks and stays. Wanna see for yourself... Take the 2 hoses off at the engine ends and drape them over the right fender. Garden hose flush in one direction until the water flows pretty much clear. Now switch the garden hose, flow opposite direction. You'll do this a few times before it runs clear both ways. Come winter time the heater should perform much better. Be aware, If its the OEM heater core it might start leaking. Chit happens when we disturb old plumbing in any case. Good luck