Does this seem right? Seems like a great way to let air and dirt into the system? Anyone have any ideal what should be there?

 

its not an open port, if you look close its not drilled through. no idea why gm put that there, but its there for no reason.

 

Well then. That makes me feel a lot better about the situation.

It's like a parts bin part, and on other cars it is utilized.

 

ive never seen another gm car use that nipple, nor can i find a reason for it. the only thing i could think of is gm was thinking of using it to hook an adapter on for vacuum bleeding the clutch/brakes, but using a cap adapter works just as well.