Cadillac Repair: Overheating Caddy, radiator cap, cadillac deville

Question
I have a 1999 Cadillac Deville it is overheating when I drive as well as when the vehicle is idling I have checked for leaks and found nothing from the water pump,radiator,or any hoses

Answer
Have you tried replacing the thermostat ?

Are you sure that you can physically see coolant flow in the radiator with the radiator cap OFF and holding the engine speed at approx 1500 rpm's ?.

CAUTION. When you look down inside the radiator for coolant flow BE EXTREMLY  careful so as the coolant does not explode out of the radiator into your face.

NOTE: when you are performing the flow test and holding the rpm's at approx 1500, Put the radiator cap BACK ON the radiator BEFORE you reduce the engine speed or you will get a face full of HOT anti-freeze.