Cooling system overheat

Upper radiator hose blows off. Bought a new one and replaced. Weeks later, car starts overheating. Told to replace overflow reservoir because it's common for plastic threads to strip. New overflow reservoir and new cap. Still overheats, and coolant spews from under radiator cap. Replaced thermostat and thermostat seal. Drained radiator and flushed with Bars Radiator Flush Kit. Refilled with prediluted 50/50 antifreeze. Still over heats and still spews coolant at radiator cap. Took radiator cap to Autozone and got a new one. Still over heats and spews. Took back to Autozone, they claim that the threads look fine and cap is in perfect condition. They told me it sounds like air in system. I bled the system. Still over heats and spews. Found more info on bleeding air out. Removed overflow reservoir cap, opened bleeder valve by the thermostat, started car. Constantly kept coolant level in reservoir at absolute max, while letting the car run for 10-15 minutes. Closed bleeder valve. Car still over heats and spews coolant. When car is driving in city, the car runs perfect for about 30 minutes, unless I'm driving up hills, then 15-20 minutes, before overheating. I drive on interstate to work; car will stay at 1/4 mark on temp gauge until I leave interstate, where temp will rapid move to 3/4 mark, and coolant can be smelled, and spews when parked. When idling, car runs fine, until I rev the car; at this point car will get to 215 deg F (a sliver past the 1/2 point on temp gauge) fans kick on until temp gauge is at about 3/8, then they turn off and coolant spews out of reservoir at the cap. The coolant temp sensor works wonderfully, the fans work wonderfully, I have inspected the water pump (no noises, no play in the pump when rocked so no bearing wear, no leaks from weep/vent holes), new thermostat and seal, new upper radiator hose, all hoses feel warm or hot to the touch and have pressure in them (hard to squeeze). I don't what else could be the problem. I am thinking I need a new radiator, but am doubtful that it will fix the issue, it almost seems like coolant doesn't get to the radiator at a certain temperature. Any ideas on what this could be caused by? Or how to fix it?