learn something new everyday then lol. ive never seen them before i found it odd as around here in maryland when you buy a new set of intake gaskets it comes with only the egr restriction plates. but now since im on the computer i can see the the pin hole in yours guess its for letting air out of the system when you first fill it up

 

Me too, never seen anything like it but it did explain why it was overheating driving around town. But now that I see this and the crude built up it made the decision easy to just pull the heads off and see what else I find. Can't hurt to look at the cylinders and get a valve job and new gaskets are obvious. Thanks for all the suggestions and help.