The radiator sould not get no hotter than the water. If your thromestat ( please forgive spelling) say 180 than the radiator sould not get hotter than that or something is making run hot. But it can go up to atleast 210 before any damage is done
Had this happen once. Found out the thermostat was'nt opening. Replaced it and everything worked fine.
Watch your heat gauge, if after a few minutes of the engine running and the gauge goes from...
The cooling system is closed, and unlike NASCAR there is no fail safe way for fluid to escape if it overheats. instead the pressure will force the fluid through the weakest point in the system....