Jon,

This past weekend I replace several of the small hoses on my 2.1 L waterboxer,
and let some coolant escape.  I'd say about a gallon.  How can I tell if the
system needs to be bled.  I added antifreeze to the resevoir to fill it up, but
what what you said about pressure and air, I'm scared.  How can I tell if air is
in the system and it needs to be bled.  I've heard that the 2.1L has the "ring"
around the engine which acts as a self bleeding mechanism.  Ever heard of this?

Charles