Can a coolant flush plug up a heater coil

Checked if the hose coming out of heater core is cold or room temp. (you called it the heater coil). The hose should be above ambient temp to somewhat hot. This will let you know, to some degree, if fluid is actually flowing through. I doubt the coolant flush plugged up the heater core. On the off chance it would, you would had to have some serious debris inside already. If its completely clogged you would get ambient temp air, like just putting a fan to your face.

Unfortunately I can not follow up on this. The car is my daughters and she lives out of state. We were visiting last weekend and I was only able to give it a quick look. From some searching this seems to be a chronic problem for this model. She has a mechanic that she trusts and I wanted to give her as much info as I could for her to relay. Thanks for your reply.