Was coming home from work just driving along at 45mph and I heard this random knocking and horrible screeching sound. What could be causing this? I just added in new oil a few days ago so it has plenty. Could this be the timing chain tensioner issue that I keep reading about?

 

&%#$(&@$% Its a spun bearing I'm 99.9% sure. Is it worth trying to fix?

 

Sounds like something from a science fiction movie. If it's running rough I would guess a dropped valve seat.