went through all the mitsu tech manuals and they do not reference the little hole in the back of the engine (left under the PCV valve). I have noticed 1 or 2 times that drips of oil came out. if the pcv system and vent side is working properly, why would oil drip through this hole?

 

bump
anyone know what this is?

 

pictures would help

 

 

It is a breather hole that goes through into the area where your coils are located. I noticed it when I did my cams. Take the sparkplug cover off and you can see where it goes inside.

 

Correct it is a breather or a drain in case water gets in that area it can drain out

 

In case water gets in the valve cover?

 

nooooo in case NOS gets in tehre!!!