I waited a few hours to jump in here . . always feel like a dick for trying to answer everyone's technical q's
Anyhoo, once the car has reached normal operating temperature, you should feel pressure and flow in the top radiator hose; that'll tell you if the thermostat is working. If you can easily squeeze it, then your t-stat could be stuck. But my guess is that you have air in the system, just gotta bleed it . . it's the usual culprit for weirdness like that.