[jhv48]

If the fans aren't turning on, then the hot water isn't getting to your radiator. When the temp gauge climbs higher than 212, feel the upper radiator hose and see if it's hot. If not, thermostat isn't opening to allow water to circulate through the radiator. If the hose is relatively hot, then you have a pocket of steam in the engine giving your temp gauge a false reading. If your engine temp really did hit 250 degrees, when you shut it down, your puke tank would have puked boiling coolant all over your garage floor.

Two possible things:

1. Thermostat not opening/installed backwards. Probably not the case here.
2. Air trapped in the engine. Go on you tube and there are many good videos that tell how to burp your system. My bet.