Phil, I don't have an answer to your question, but I'll just tell you what I do. At every annual I pull this filter and check it (never have found anything) then just snug the nut back up semi-tight. How's that for professional terminology? I think the important thing is to replace the lock washer/gasket with a new one and bend the ears over to lock the nut in place. I get mine at Spruce, p/n 07-01388, Marvel p/n MC16-A48.
