hard drive noise

Well today i put my hitachi 1tb in my 5" drive with the sythe silencer kit (actually works !), now ive put in my 640gb as it was left unpluged after sorting out my pc. After a few hours ive noticed this sharp clicking sound, now i know hard drives make a normal clicking sound but this is about tripple the level of the normal seeking/writing you can hear, its only happened recently and i cant find the cause but i think its from the hitachi drive. Is this a sign the drives dieing? im doing a scan on it but it has an hour left..

It's possible that the drive is on its way out. The (extra loud) clicking, is likely due to the drive trying, repeatedly to access bad sector/s.

Go to http://www.hitachigst.com/hdd/support/download.htm and download the Drive Fitness Test, run this and it should tell you if there is a problem with the drive, and you can then tell the retailer the results of the test (it may speed things up with a rma).