I'd guess you have something going on causing the coolant to overflow. First I'd look into the things you're doing different, i.e. you running the A/C, drive more city, more up hill or more aggressive. If you're not doing any of these, then I'd look into the things you replaced 5 years ago. Make sure your waterpump is not leaking out of the small hole on the bottom, makes no noise and when opening the radiator cap at start up you can see the coolant flow when the car is starting to get warm. Look into your fan clutch if you have A/C and make sure its tight and won't spin more that a turn or 2 after shutting the engine off. Run the heater making sure the thermostat opens up fully and check the radiator for leaks. Pull the oil dipstick to ensure no coolant in oil - you don't have head gasket issue.