Really? I'm no spring chicken but I've never heard anything from a HDD that I would associate with bad sectors. I've heard a nasty whining noise when the bearings are giving out or it has been switched when too cold, and some uncomfortable grinding when trying to recover from a "parked" state (a reliable way to hasten the death of certain types of drive), but that's it. Given that modern drives transparently replace up to a certain number of bad sectors themselves you're unlikely to hear them do it anyway. Surely you're just hearing the normal "ticking" sound when the drive head seeks across tracks?
All said, it's still probably worth backing up your saves anyway.
Jim