the way i do it is to open rad cap, idle car till the fans come on, (that way you know the t stat opened) top off the rad if the level has dropped, open the bleeder screw 2 or 3 turns, till a stream of coolant comes out.

you can also squeeze (softly) the upper hose to get any air that may be caught up in it too.

if this still fails you, you can remove the t stat housing, and pour coolant right into the lim till its full and redo the above steps.