Weird under hood noises

Hey everyone. Last night I was hanging out with my friend at his work and he happens to be a mechanic. My car was at idle cuz my turbo timer was activated, blah blah. Anyways...my friend told me he was hearing a knocking sound. My car has under 50,000 miles and I am on the ball when it comes to the routine oil changes. Amongts (sp) that, the bearings in my clutch are bad, could this be contributing to the noises under hood, or could this be more serious? Thanks in advance for any replies you guys may have.

-Chris