Oil fill neck
 

Anybody ever had to replace the seal or o-ring between the fill neck and valve cover
have a small weep going on.:humm:
On an 03 7.3l

I don't see how oil could leak from there really. It just funnels the oil down into the engine, do you have tons of blowby?

No blow by at all it is wet around the bottom of the neck where it attaches
to the valve cover

have you tried to clean it off and see how long it takes to get nasty again?