Has anyone seen this? I was losing coolant, but couldn't find the source under or around the engine. Then I noticed water stains on a black pipe that takes the coolant from the top of the radiator, across the intake manifold!

About halfway along this metal pipe is some kind of attachment point (maybe an air bleed?) with a plastic plug. And this plug looks damaged. Is that all it is? A plastic plug? Guess I should be able to order that little bugger.

 

yea, the pipe plug does leak at some point and needs to be replaced