DL560 +CentOS5.3 (RHEL5.3) fan drivers

[Pinhedd]

I got my hands on a pair of HP ProLiant DL560 servers that came off-lease. I loaded one up with Windows Server 2003 and had to install an easy to find fan driver from your support section in order to get it to quiet down (which it did). I loaded the other one up with CentOS5.3 but have not been able to find system drivers that will quiet the fans down. I read somewhere that this is controllable by 'health' and I installed the rhel4 package hoping it would be binary compatible but haven't had any luck so far. I tried a rebuild as well but that hasn't worked either. Can anyone point me in the right direction or tell me if this is in fact possible? I cant afford to have a jet engine running in my basement 24/7.