HELP!!! Fan Blades hitting engine damper/harmonic balancer

[aplatz]

What is the cause of this? High miledge, excessive heat from over heating? Is this a item that should be replaced before it fails? If so at whar miledge os recommended? When replacing the serp. belt, what are the tell tale symptoms? Excessive wobble, misalignment of the pulleys?

 

[xzalt]

I'm at 136,400, and my belt didn't look horrible, but I did have a loud squeeeeeel that is now gone with the replacement of the belt and HB/D. So thats the infor for my jeep.

thanks again to all who posted and helped me out!!