I did the same thing I even pushed water through the heater core. Then I used an air compressor to push the heater core fluids out, the block and the radiator through the bleeder. The engine drain bolt is sensitive make sure it’s not over tightened just enough so you know it won't turn itself and leak it’s a 3/16 and push it in deep then turn.
The bleeder doesn't have to be tightened completely either and when the coolant reached the top it started leaking out, as it was wet turning the bleeder just got harder.
Is there any tool to turn the bleeder?
I had to use pliers and it looks bad, using your fingers didn't work.
You have to take the reservoir cap off to bleed the system, nothing bleed until I did that and the bleeder was almost off after adding new coolant. I just couldn't see how it can get into the heater core since those hoses run from the top. When I turned the heat on before it made a bubbling sound I think it's gone now.
Are you suppose to run the heat when you add coolant with engine on?
I think it helps the fluid flow around and fill up.