You figured it out.  It is an air bleed.  Any air that could be in the
engine floats up into the engine coolant rail that goes around the engine
bay.  That is the whole point of that rail.  It allows the 2.1l to self
bleed after a coolant change or loss.  Just FYI.

Thanks,
Ken Wilford
John 3:16
http://www.vanagain.com
http://www.strictlyvwauctions.com
http://www.eurovan.org
http://www.vwcabrio.org
Phone: (856)-327-4936
Fax: (856)-327-2242 

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Edward Duntz
Sent: Friday, April 28, 2006 12:29 PM
To: vanagon@GERRY.VANAGON.COM
Subject: thermostat cover nipple

In doing some work on the '87 Wolfsburg last weekend describing that and the
troubles I encountered would require several more posts) I discovered that
someone had broken off the small house and nipple that comes out of what I
would call the top of the thermostat housing, but which parts places call
the thermostat cover. They had stuck a nail in the hose and some epoxy
around it, so that it plugged the hole left by the broken nipple, and also
restricted anthing that would have flowed through this small hose.

I got a replacement cover, but when I looked inside I became puzzled. The
bleed screw sits on top, and this nipple seems to come from the top near the
bleed screw, but the only hole is less than a mm in diameter and looks like
it is only for bleeding air. So what does the hose do that comes out of this
nipple? It goes to the rail that surrounds the engine compartment. The hole
looks too small to carry any meaningful amount of coolant. What's going on
here?

Ed in CT