03 impala, overheating problem, mystery cracked hose

Just wondering if anybody can name this mystery hose, so i can get a part number and replacement without having to go back to dealership and digging back deep in my pocket, i know water runs through it, its shaped like an L and steam comes out of the crack and the engine runs hot within five miles of drivin it, its more of a plastic feeling type of hose than rubber, any help would be greatly appreicitated, thanks!!

http://img199.imageshack.us/i/dscn0637r.jpg/

There are two of them and the tensioner will need to be removed to replace them. The one you have pictured is the top one. if you look down under the tensioner you will see the other one.

http://partimages.genpt.com/partimages/395229.jpg
#BK 6601736 at your local napa

Or call your dealer, they will know exactly what you are talkiing about as they fail often.

I had to replace mine less then 2 months ago! I got mine from autozone for around $5. It was fairly easy to replace, I had to remove the alternator, belt tensioner and sway bar. I went ahead and replaced both of them (there is one hiden out of view). Mine also were so brittle that they fail apart as I pulled them out. So I had to make sure to dig the plastic tips and o-rings out before installing the new ones. Good luck. Let us know how it went!