Need help identifying a part, sorta

[bluecb7]

First off this is a t-stat housing as tho you were looking directly down at it in the engine bay. Okay so I know the hose circled in blue is for the TB coolant or something like that. But the hole circled in green, this is the only t-stat housing that I have seen with this threaded hole even cast in to it. Any ideas what the pieces circled in green goes to? And if it is relevant info I just got to thinking about, this Housing came of an a6, 9091 i believe. The one I have is an a6, but is a 9293 and doesn't have the hole circled in green.

[psychogat3]

does the hole in the one circled in red go all the way through? it looks like a plug to me.

[shadowdlink]

Maybe this can help?

Water hose layout
Water pump layout

[PhatAccord]

i believe that the one in the red circle is a bleeder valve

[JoshM]

i believe that the one in the red circle is a bleeder valve

I believe in your beliefs.

I don't know the green circle though, and really don't feel like going outside to look under my hood.

[PhatAccord]

i think the one in the green circle is for a 10mm nut and a bracket that holds the hose (blue circle) in place...not 100% sure though just trying to remember off the top of my head...

[bluecb7]

Thanks for the inputs and the links. The water pump layout has the part circled in red as a "bolt, breathing water", so I'm going to agree with you guys.

The only thing that would lead me to believe the one circled in green was not for a bracket is that the hose had no evidence of a bracket ever being around it.