Advice On Troublesome HDD

[JonnyAlpha]

Some time ago I started a few threads as I was having trouble with the Zpool Status which I belived was a problem with the Hard Drive, I was getting alerts saying the Volume was in an unknown state, the Disk disappeared from the Virtual Device, then it came back, then it had Checksum Errors and then after some messing around it sorted itself out and has been fine since. yesterday the same problems occurred again although the Disk did not disappear it started to show Checksum errors in the Volume Status. The alert icon was yellow but know I have just turned on the NAS box to "OFFLINE" the drive and remove it but the damm Alert Icon is now GREEN and reports that the volume status is HEALTHY!!!

What's going on? Is the HDD still faulty or is this a FreeNAS hiccup?

I set up an RMA but did not pursue it, its still valid and think I should just send the drive back? I tested the HDD with Western Digital Data Life Guard but no errors where found, I do recall however find problems when I ran HD Tune but I cannot find the pictures now as I had to re-install Windows 7 (Another Problem) and foolishly did not save them!!

 

[JonnyAlpha]

UPDATE:

Sorry whilst I was typing this the drive mad its (familiar head reading noise) and on checking the zpool status it now has 3 checksum errors and is once again in an unknown state!!! I will now OFFLINE the HDD and return it, if they find nothing wrong with it I'll contest or simply have to bite the bullet and get another drive!!!