Just had the same thing happen to me with my exhaust manifold bolt(s).
I have 79K on my 04 and started hearing a sound like air escaping on
start-up. After some time the sound goes away. Upon inspection I found that my
exhaust manifold bolt had completly snapped off and only a small
part of the treads remain.
I located the bolts at a local fastenal dealer - here is the link for anyone interested.
http://www.fastenal.com/web/products...1115929&ucst=t
These are Grade 90 bolts but you can also get the 10.9 Grade but since I
am going to all of the trouble to replace them...........for $18 who cares.
I would rather use Grade 90 and be done with it.
Appearently this is a common problem with H2s. Little did I know.