Have you looked at the engine thermostat?
You should realize the problem a little more, that is, it is heated when it is stopped in a jam, or is always heated even if you are circulating at 100 km/h? How long does it take to throw the water out?
These two questions are very important to guide you in your fault. But anyway I think the thermostat that is in the butt and that opens the passage to the radiator when the engine reaches its working temperature was fucked.
Sometimes they break and stay closed, preventing the circulation of water and causing what you mention, to check it, it is enough to start the cold car, and keep it at about 2000 rpm while touching the radiator panel with the hand or the tube that goes from the radiator to the cylinder head warm and then begin to warm up until you can keep your hand without burning.
If the engine reaches 100ºC and the hose is still cold ... bad, broken thermostat, and if on the contrary the hose is heated just as fast as the engine, the thermostat is broken, but in this case it has been open, (it is not your case).
Another thing that can also be is the breakage of the water pump, which makes the water not circulate and that the heat of the engine does not dissipate. To see it you just have to start the engine and look at whether the water circulates in the expansion vessel or no movement is appreciated.
All the best.