helllp with cooling issue

A 180 degree thermostat doesn't keep your coolant at 180 degrees. It opens to allow flow at 180 degrees. Your car will normally run hotter. From what you are telling us I would question the gauge's accuracy. 225 is over the boiling point. When you open the cap, the petcock, whatever and release the pressure, it should begin boiling immediately at 225 degrees. That is doesn't and the coolant from the petcock is cool tells me you should try another gauge.