Test: leave the t-stat out, fire up, see if water in radiator is flowing or static.
I'll assume static check of fan wobbling shows none, and no noise from water pump indicating breakage.
Fan clutch ? Direct drive fan ?
If no circulation, there's either a blockage or the pump isn't working.
Blockage could be anywhere in the system (upper or lower hose, pump, housing, block, heads.
Do you get any heat out of the heater ? (Not that it could cause that problem, but it'll be a secondary symptom.)