[Appleman]

My PowerMac G5 Dual 2 GHz makes quite some noise: the Drive Bay fan rotates at around 4000 rpm.

I opened up and cleaned all the dust, specially the graphics card fan (Nvidia) was completely blocked.
However, after starting up it quickly became loud again due to, again, around 4000 rpm of the drive bay.
Temperature of the drive bay, however, is lowest: 33 degrees Celcius (± 99 fahrenheit).

I have two hard disks of 1 GB inside. Is it possible that if one of the hard disks is going bad, the fan starts to get up?
Thanks!

[chipchen]

Could be the fan going bad too,.... you can probably get a replacement fan from an Apple Authorized Service Provider or online somewhere...

[Appleman]

Well, I found that it in fact really has to do with ambient temperature: when it's cold, or I point a big external fan on the PowerMac, rpm's do go down, so most probably it's a matter of placing the Mac in a better place where more air can access it.

[vlady2k]

Originally Posted by Appleman 

Well, I found that it in fact really has to do with ambient temperature: when it's cold, or I point a big external fan on the PowerMac, rpm's do go down, so most probably it's a matter of placing the Mac in a better place where more air can access it.

maybe, fans needed some lubrication.