WD2500KSRTL Operating Temp?

What would be a good normal operating temerature for a  WD2500KSRTL  Sata II  Drive?   I have one that is only about one year old but it seems to run hot!  All  fans are working properly. I went ahead and added a new slot case fan to try to cool it down even more. Most of my drives operate in the 30 - 40 degree C.  This drive seems to go

between  47 - 58 degree C. even with the new fan. Could the bearings be going bad and should I consider getting this one changed out soon?   Thank You