Best thing to do to keep your radiator functioning efficiently is to make sure your radiator caps are in good condition. Radiator caps contain a spring that activate around 15psi to release excess pressure. In optimum condition, this rarely happens, and your radiator is kept tightly sealed, meaning your coolant does not evaporate. Adding (ethylene glycol (EG) or Propylene Glycol (PG) ) antifreeze, raises the boiling temperature of the coolant to 255 Deg F or about 124 Deg C. Water evaporates at 100 Deg C. Keep ratio of antifreeze to water at 1:1 or maximum or 3:2. Too much antifreeze reduces the coolants heat carrying capacity.

Don't use tap water! or mineral water..These contain minerals that will build up as rust and scale. Distilled or demineralized water is best.

Lastly make sure you have your cooling system is tightly sealed, and check level of coolant consistently.