OK...

1. replace the radiator cap (on your car it is not on the radiator. Instead it is on the pressure tank). The reason is that the radiator cap is the easiest and cheapest fix and will eliminate this as a possibility. These caps hold a specified pressure and that elevated pressure changes the boiling point of the coolant. If they don't hold the correct pressure, then they will allow the water to boil. Get the radiator cap that is specified for your car.

2. Make sure that the coolant level is correct

3. Check to see if the radiator fan is turning on when the engine is getting hot. Also check to see if the fan is turning on when the AC is turned on. If the fan is not turning on with the engine hot, then the fan motor is faulty or the fan control circuit, fuse, or relay is faulty.

4. If all the above is good, then it could be the coolant system which includes the thermostat, plumbing, radiator, and water pump. These items are the most difficult or expensive, so make sure the other systems are working properly first.

Good luck