Hi my friend! Of course the drive failed because of the bad construction of cooling in these desktops.I cant understand what Apple thinking when was making these all in one machines..Maybe is only for Antarctica? :) I have seen temps in hard drives more than 50c and continiously..They cant last like that..The most is 37c at continuous operation..Of course Western digital hd's can last longer than any brand( not the blue).
The only solution is to install a third party software to control fans and the only one that is working as i said some months ago is : http://www.derman.com/iMac-Fan-Control
Dont search anything else is not working like this at least for my mac.
then join the two point connector together itsself. The next thing is to put the hard drive outside the aluminium case and put an fan from desktop tower on it with a case for external drive and then your hd will be work at most in 32c.
That's it.