G5 Fan runs very fast, machine locked up

[TommyMacBrown]

Thought the house power had gone off because when I returned home, my Mac was off. Rebooted checked email, and went to get breakfast. Came back fan running very fast, and machine is locked and no video. Turned off by holding in power button. Same thing happens when I left again. I have now been on the machine for over an hour and no problems. What is causing this?

Dual 2.3 PowerPC G5

Thanks for your help.

 

[max¥¥]

not sure if your mac is a water cooled model but maybe you should check to see if it is leaking

 

[666sheep]

not sure if your mac is a water cooled model but maybe you should check to see if it is leaking

2.3 are aircooled (both). No leak possible then.

OP, you got Sleep mode enabled? G5 crashes when it's going to sleep?
Try reset PRAM and PMU first, run Hardware Test (MRoogle or Google for how-to). Post results.
If it won't help, next to check should be graphics card (if you have spare, any G5 AGP card will be good for that - i assume that your G5 is AGP one i.e Dual Processor, not Dual Core).