hey guys, recently i replaced my heater core, along with flushing the block, radiator and replacing the thermostat with a 185 F unit on my 3.1 cavalier. well after all this and burping the cooling system, it wouldnt reach operating temp, stopped around 140 F. i drove it like this for awhile and finally decided to replace the tstat again with a 195 F unit, but i still have the same problem only now if i let the car idle for 10-20 mins it will reach operating temp but as soon as the thermostat opens it will drop back down to 140 F. Also while cruising it sits right at 140 F. I was thinking maybe the coolant temp sensor but I didnt have this problem until i changed the thermostat. anyone have an idea of whats going on?