Fan noise


My G4 started to make more than the usual noise. I'm sure it is the fan, more on that in a minute. I took to the "Genius Bar" we ran tests all was fine - naturally - but now I have a dilemma. Though I have an open case number, my 3-year (yes, I've had the system for THREE YEARS!) Apple Support has expired as of Saturday. Here's the question: Since it has gotten hotter and I've put on the A/C, and I have a floor fan on me, the noise has abated somewhat. Should I purchase a fan and install? Is that easy? Should I pursue Apple to replace it anyway (I could say I had a case number prior to the expiration)? I'm sure it's a thermostat thing. I run Panther...though...and I even attempted to boot up in OS9, download the "fan fix" and reboot to see if that would help, but I couldn't remember how to get on the 'net in 9. No seriously! I couldn't find my Safari or IE for that matter in OS 9 apps etc.

So, what should I do about this fan? Thanks.