Bomb???

[SHOWMX <SHOWMX@aol.com>]

Sorry for the stupid question folks...  But, I'm new to the list and while
searching the archives I keep finding references to the "bomb" replacement.
What is das BOMB?

BTW, I'm hearing a high pitched whine when my 4k is between cold and fully
warmed up around 2700 to 3000 rpm.  It behaves normally while hot.  This sound
is similar to what I heard when my idler pully was diagnosed and replaced.

I'm thinking a water pump or alternator bearing, or is there something else I
should be considering too?

TIA,
Briand
'87 4kcs