2004 Pontiac Grand Am

I have a 2004 Pontiac Grandam GT 3.4L with 91,300 and for the past couple of months I have been having problems with it overheating. In the beginning the coolant light would come on, I would fill the reserve tank only to have to do so again later in the day. This would continue for a day or two and then it would be fine for a month before completing the cycle all over again. We did replace the radiator. However after a couple months the problem has restarted and much worse. For the past four days I have constantly had to fill the tank and when it heats past 230 you can hear a rattling noise from the driver side of the engine. My brother did discover a drip on this same side in the engine. Do you have any idea what this problem could be?
August 15, 2007.

Replace the thermostat after this try to find where the leak is. Remember one thing leads to another and could be a major problem at the end with the engine.

Aug 15, 2007.