2004 ST with the one (single) sensor in the thermostat housing. Have some minor coolant seepage between the low and upper housing, and same with the temp sensor area. Went ahead and purchased a new housing kit, thermostat, small lower hose, and o-ring for thermostat. Honestly, after reviewing the project section and seeing how it all works I probably only need a new o-ring for the thermostat and new seal for the temp sensor. Regardless, I don't have a new sensor o-ring and calling Ford parts I can only get the o-ring by purchasing a new temp sensor for $40. Will a generic o-ring work, or is this seal more that a simple o-ring design? Has anyone just replace the upper seals (thermostat o-ring and sensor o-ring) and had it successfully seal? Is the lower seal also an o-ring that can be replaced, or is a new lower housing a requirement?