I just suffered my own purgatory with my cooling system.1) check water pump
belt for correct tightness. 2)  follow the bently bleeding procedure starting
with a cold engine. 3) idle at 2500 rpm . You should get some coolant flowing
( 1/2 to 3/4 turn of wrench at a dribble. if not check that the bleeder is
not pluged up.
Befor you do any of the above visit ben's site ( huotx@videotron.ca ) cool
site lots of diy info

Jim Morgan 86GL
"Breadbox"