G5 fan is really loud

dr fever-

Start with the ubiquitous SMU reset and see if that helps.

Luck-

-DaddyPaycheck

Sigh, I was having the same issue with the loud fans and crashes, so I followed the instructions to reset the PMU linked above. Now the power light comes on but the hard drives never spin up. The "cure" is worse than the disease!

Dual G5 Mac OS X (10.4.8)

OK, did some more research. This is a known possible side effect of of resetting the PMU. I pulled the battery from the motherboard, walked away for a few hours, then plugged everything back in and it worked. Crisis averted.

dr fever-

Does this document help with finding the battery?

Luck-

-DaddyPaycheck

If Your Fan Is Loud Then You Need A New (Motherboard) or (Ram). Thats what my powermac was doing. My Powermac G5 Dual Core 2.3Ghz is now very quiet.

Powermac G5 dual 2.3Ghz PowerPC Mac OS X (10.4.8) 2 Gig Ram

Can you describe how you decided which to replace? Or did you replace both (motherboard and ram)?

If you have the Apple Extended Warranty, those are still good on computers purchased up to 2004, I think. Mine expires this October. Get it done if you're going to do it. A new Motherboard was almost as much as a new computer, costing over $1000. The AEW covered it so all I had to do was wait it out.

Does AppleCare cover a motherboard replacement as well? I still have a year left on my Dual 1.8's AppleCare....I still get revving fans after RAM replacements and all.

PowerMac G5 Mac OS X (10.4.3) Dual 1.8

I just had the Logic Board (mother board) replaced on 2 G5's in my classroom. I called tech support and they sent a tech out 2 days later and replaced them both in about an hour. They were both under AppleCare.
The symptoms:
1 had revving fans and would randomly lock up

1 had a failed power supply (the power button did nothing)

Both are working smoothly now.

I was experiencing this same problem on my G5. Loud fan during light duty.

Try what I did. Shut down, unplug everything, open up the G5 and clean out all the dust with a can of compressed air.

I was amazed at how much dust accumulated in there!
especially around the fans.

It's worth a try. It's quick, easy and cheap.

couldn't hurt.