Rheem gas hot water heater. 2014 date of mfg and installed. leaking from top of tank. hot and cold connections are clean, no water or corrosion. its coming from around a plastic collar that has a bolt in it. assuming that's the anode. could it be the anode is loose? can I drain the tank and lift up the top of the tank cover to see where its leaking? or is it always a failed weld joint? is 6 years the average life of a water heater? are Rheem units cheaply made? thanks, john