That little hose that's on there looks innocent, but the thing just won't come off. Suggestions?

Is there a freeze plug in the head that's supposed to be right next to the egr? There's a hole right next to it, that's sits at a slight angle, that's threaded..but it's open.

 

its really tought to get off, but i just wiggled it and it came off...eventually. try squirting some wd-40 on it to loosen it up a bit.

and i have no idea what hole you are talking about. sorry.