Has the case got good ventilation?
I like cpuid hardware monitor personally. 56C definitely seems hot but hard drives can operate up to 60C just fine. Still heat isn't a good thing and a normal operating temp for an hdd should be in the low 40's at the max. speedfan has a SMART test you can use that tells you your HDD temps specifically.
old drive or not thats an awfully high temp. you could buy an hdd cooling enclosure. that might help. beyond that I don't know what you could do
I have never once taken the temps of my hard drive. Didn't even know you could or needed to do that. Good job getting it cooled down though.