I have a 3.5" hdd in a caddy probably permanantly. I am going to use it for my new eurovox ex7000HD. It will probably be on about 15 hours a day and about 4 hours to cool. The fan included inside the caddy is unusually very very loud. if i disconnect the fan the noise is fine. would the HDD overheat from this much use without the fans.
I'm not really sure, but there are numerous 3.5" enclosures that don't have built-in fans, and the hard disks are fine. I suggest you find a way to keep tabs on the HD's temp, remove the fan, and see what happens.