Another coolant puddle

[pilut2]

My 99 Base has about 41K miles it is not my daily driver. A couple of months ago I added some coolant because it was getting close to the min line on the reservoir- at the same time I updated the cap with the latest 04 version. Since then I have had occasional puddles inboard of the right rear wheel. I have opened the purge valve for 3 or so heat/cool cycles but the condition persists. I have pulled the rear carpet and styrofoam insulation and there is no evidence that the coolant tank is leaking, at least into the trunk. The water pump is not leaking. It appears that my coolant is overflowing when the car reaches full operating temp as the coolant rises from mid point in the tank to way over the max line. My temps seem fine only reaching the 0 on the gauge after spirited driving- usually the needle sits between the 8 and 0. Is it possible I just still need to burp air out of the cooling system?