Yeah im not aware that the pump would damage itself if dry run...i really doubt it in fact.
But maybe pump was cavitating if being starved if you omitted bleeding the system.(a cavitating pump can make a hell of a racket but wouldnt be screeching)

Id have a good go @ ensuring you have it bled right...get the engine good and hot so the stat is open and start opening the bleed valves to get the air out of it.


Marty.

Ok will give it a go... Thanks I'll be back with an update.

It's two months later and all seems fine.. So it looks like it was the tension pulley being too tight causing it to flip up and go super tight jamming the water pump or am I talking codswallop?