Cadillac Repair: cadillac, electrical wires, water pump

Question
i have a 94 sts i just put a new radiator in and it over heats at 250  but my last radiator only ran 198  212   but leaked so i got a new one  i have a new t stat and water pump what can be

Answer
IS or HAS the CHECK ENGINE light illuminated recently and or did it just start to illuminate ?.

You DID install a new thermostat ?.

Check around the area where you performed your work and look for any loose electrical wires. Especially any BLACK colored wires near the battery.