while closing the bleeder screw, part of is snapped off: http://grdlock.kicks-***.net/public/Pict0154.jpg

the very small tip broke off. Can just the bleeder screw be replaced or do i need the whole stat housing?

 

TTT

 

Looks like just the bleeder part. As long as there isn't any damage to the housing (stipped threads), I'd say it looks fine.

As far as the bleeder, it looks like you busted the bleeder part that you screw in and out, but there is also the grommet (don't know exact name) that screws into the housing.

Here's a pic from shoebox's website...hope it helps.
http://shbox.com/1/bleeders.jpg

 

mine didnt have a little screw like that one, so I unscrewed the entire housing. Little did I know, it was just a tiny bolt, not a screw, that needed to be loosend. It came loose, and shot coolant everywhere(on my opti as well). So when I went to tighten that down, it snapped off

 

Did the same thing in a buddies when I was gently tightening it with my tiny 1/4" socket wrench. It looks like you can just screw out the main part and then screw a new one in there.

 

looks like part# 10070107

 

Get some Vice grips and tighten it till you get the part. Well, thats what I would do if it wasn't leaking.