I hear this sound in my internal WD HDD and I don't know if it's a regular sound. I hear it randomly, it's a low volume rotational sound (with a high pitch) like whatever rotates is rubbing or needs lubrication or something, it happens for a second or so and then stops (hard to describe, and record as well it's low).
Does any one know a software that could test the motor or the internal mechanical parts performance, so I can find out if there's anything wrong?
You can get free diagnostic tests from the drives manufacture site. Spinrite http://www.grc.com/spinrite.htm works the drive to see if it produces any errors. It is hard to tell these days whether a hard drive that makes a sound means imminent failure because i had one that didn't really make any noise and it failed, and then another drive that has been making noises but has been working fine for the past 2-3 years.
My suggestion is to make sure you have a backup of any important data on that drive & if you run an OS on it, if possible make an image of the OS (with a regular backup weekly, monthly or so depending on how often you add new programs, ect. ) so you don't have to go through the process of reinstalling everything.
I don't know if tests that do a SMART self test or do a full surface scan for bad sectors could do any good for me, I'm looking for something that could benchmark or test the performance of the HDD internals,...
I use HDtune and its free and works fine for me also try to use Microsoft(computer then find drive that is causing issues right click on it and then select properties and then go to tools then check now and then select both options and then restart PC let it go through all its test and keep in eye on it.