this is the small fitting on the bottom side of the rad hose gooseneck for the top hose. it faces the bottom and towards teh back of the motor. i dunno what its for cause i have everything routed. its not a breather its for a small line like one of them going trough the iac but those are all routed. if you know id love to know where it belongs

 

really? no one at all can help?

 

Goes to the nipple on the thermostat housing.