Okay so some background, I have oil leaking under my 2005 F150 4.6l truck and I'm currently attempting to replace the gasket when I found this open port that I cannot identify with the use of google.

This pictures has arrows pointing to the port in question. The perspective is from me under the truck with the front of the truck being in the back of the picture. The picture is currently looking between the left front tire and the left side of my oil pan.

This may not be the source of anything but I still don't have a clue what it is so if anybody can give me some insight then I could learn something at least.

 

did you found out what it was.
possible that the port is being used on other side of motor and that one seal i can check mine too if its like that tomorrow