Radiator leak

I have replaced the radiator and water pump, due to a leak that was causing the engine to over heat, a few months ago. In the last few weeks, something up front has started leaking again, either the radiator or a hose, but if the AC is on it does not leak. If the AC is switched off it will steadily leak, but I am now going on the third day of the reservoir still being full after leaving the AC on. Any insight as to what this means? Or what I may need to replace now?