Bleeding the air with hose=had coolant coming from the threaded part of Inverter Bleeder Valve

I suspect you're mistaking coolant falling from the valve top as coolant leaking from the valve bottom.

You probably followed the consensus of a 1/4" inner diameter tube. Try a 3/16" and wrap that willy nice and tight.

 

Maybe when the bleed screw is loosened it’s loose enough for coolant to travel through the threads. I’d wager it’ll be water tight once snugged down again.

 

Coolant will seep up around those threads. (It was worse on Gen 1, which had two bleeders, and one was on the suction side of the pump. The whole time you were trying to bleed, air would be sneaking in around the threads on that one.)

I took the bleeders completely out and put a non-hardening sealant (I used the Hylomar blue stuff) on the threads, never another problem.

 

Apply a little grease around the juncture of screw and caliper hole?

 

These are inverter bleeders, not brake bleeders. So before I smeared the Hylomar blue stuff on my threads, I looked up its compatibility with coolant.

If I ever wanted to smear it on brake bleeder threads, I'd look up its compatibility with brake fluid.

All depends on whether the bleeder is located in a part of the coolant loop where the pressure is below atmospheric or above atmospheric.

Gen 1 had two bleeders in the inverter loop, and one of them was in a below-atmospheric spot, so it would suck air in. The other one would seep coolant out.

Gen 2 has only one bleeder, and it's in a spot where the coolant seeps out.

 

Obviously coolant will leak from loose threads but I doubt it will suck air. Even if it sucks air it will be negligible and not enough to make an air lock in the flow while eventually it will find its way to the reservoir.

 

A gen 2 inverter bleeder won't ever suck air, because gen 2 only has one bleeder and it's in the above-atmospheric section of the loop.

If you ever meet a gen 1, there are two bleeders, and one is in the below-atmospheric section of the loop. If the pump is on it's about 10 inches H₂O below atmospheric there. If allowed to suck air there, it definitely will.

How much air? "Enough to make an air lock in the flow?" isn't the main concern, to me anyway. As a practical matter, it's enough that if you're watching for the bubbles to stop coming out the other bleeder to know when you're done, you're never done.