Would it make sense to stress the hard disk to test its reliability? If so, what are good tools out there?
More abouthard disk stress test needed testers
Run manufacturer diagnostic tools.
I doubt many HDD tests can detect the kinds of problems that make "terrible sounds". They may be able to detect frequent read errors causing frequent head seek operations; I'd bet the manufacturer's free test suite will do that test. But if you have a failing bearing on a drive spindle my guess is they don't build in vibration analysis systems. "Stress Testing", on the other hand, sounds like working it hard until it fails. Then what? Once it's failed it can be hard to recover.