What saltfish said. My 200g WD drive could double as a cigarette lighter
Get some air flowing over those drives!
You can get a 5 1/4" hard drive cooler module pretty cheap.
Otherwise, and this is why I build exclusively with these cases, Raidmax cases drop the hard drives directly behind two of the 80mm case fan mounting areas. Two more case fans are below them. So far, one fan in front of the hard drive and one fan below that (plus the side fan) has kept my case nice and cool and my drive running with no complaints.