I have a 7.3 diesel and noticed fuel on the ground the when the truck sits overnight. I was able to locate residual fuel on the filter housing so I just installed a new Fuel filter, O-ring and Cap. I had the parts supplier print me an expanded IPC pic of the filter assy for a reference. One thing I noticed, is that the new assy was supplied with 2 O-rings, 1 for the cap and another im thinking goes around the lower part of the filter in a platic groove. The problem im having is that the epanded view does not show or mention in the diagram to install this second O-ring. I feel that without the o-ring you would have no seperation from what I see is 2 differnt filter elements. The previous one I removed did not have this second oring installed, and it was changed just before I acquired the vehicle last Aug. Is that unit meant to have an extra o-ring for a different application or was it right to place the other one on even if the diagram didnt show or mention its install. Secondly, If the leaking persists after these parts change, Would you reccomend changing next? Is it common to see the petcock leaking as well from that filter housing. Also, I noticed under the filter is somekind of wire/small pipe looking thing. Is that some kind of fuel heater?