Fan won't stop! - Pre-Intel Quad G5

[jusi]

Hello,

I've searched so many message boards about this issue I don't know what to do anymore...

First off, my machine runs fine. It's starts up, it's responsive, it's not too hot. It wakes from sleep just fine.

I've had this computer for over 4 years now and over the past few months I've notice the fan running quite a bit more than usual. I didn't think too much of it but now it just doesn't spin down at all even when the computer isn't doing anything. It's quiet for about 20 seconds when the desktop is building on starting but then the fan kicks in, revs up about 50-60% and just stays there constantly. It revs up even higher if I start multi-tasking but for the most part it stays at this level. And it's quite loud!

I've tried:

resetting the vram
resetting the SMU (PMU)
cleaning the dust from inside - but not where everything is removed and scrubbed down
running AHT which came back with no issues
ran disk utility a few weeks ago with no errors

Any ideas?

 

[chscag]

Here's a LINK to the service manual for your G5. Take a look at the section under trouble shooting which refers to "thermal calibration".

Other users have reported the same problem as you describe and one of the solutions is to do a thermal calibration. My guess is that as the unit ages, it loses its thermal calibration and that in turn is what controls the fans. Since there doesn't seem to be anything else wrong with your G5, I suggest you give that a try. Let us know.

Regards.

 

[pigoo3]

I know that you said that you did some cleaning of the inside of your G5...but some of the hardest areas to clean may be the areas causing the most restriction to air flow. For example any sort of "finned" cooling heatsinks...and any or all of the cooling fans...could be clogged with "fuzz".

Another thought could be...the G5 computers have a lot of fans in them. One or more of your fans could have "died" (I believe your G5 has 9 nine fans)...causing the remaining fans to work overtime to cool the computer. So verifying that all fans work could help figure things out.

Lastly...your Quad G5 (in addition to the cooling fans)...has a liquid cooling system for the processors. It is not unheard of for blockages to occur in the liquid cooling system...which can cause overheating as well. Sometimes the liquid cooling system even leaks coolant.

- Nick

 

[Rottie]

Nick,
Good call on the fans - I personally, am leaning more towards one (or more) of the fans bearings going.

 

[baggss]

Here's a LINK to the service manual for your G5. Take a look at the section under trouble shooting which refers to "thermal calibration".

Other users have reported the same problem as you describe and one of the solutions is to do a thermal calibration. My guess is that as the unit ages, it loses its thermal calibration and that in turn is what controls the fans. Since there doesn't seem to be anything else wrong with your G5, I suggest you give that a try. Let us know.

Regards.

That link is for the Dual and Single G5 manual, the Quads were liquid cooled and are a bit more complicated to take apart. That being said, the thermal calibration section comes in handy. I've been having issues with my Quad and I certainly will go download the tools and give that a go. Thanks.

 

[pigoo3]

Nick,
Good call on the fans - I personally, am leaning more towards one (or more) of the fans bearings going.

I purchased a dual 1.8ghz G5 Powermac about 6 months ago...and it was absolutely filthy!!! The fans & heat-sink fins were absolutely clogged with "fuzz"!

The strangest thing...the previous owner worked as an Apple repair tech. at my local Apple Store! You would think that he would have kept it clean...just like you would expect an automobile mechanic to have a perfectly running car.

Of course if the computer in question is clean...it could always have a "dead fan". Anythings possible...until eliminated.

- Nick

 

[harryb2448]

Go into Systems Preferences > Energy Saver > Options and make sure Processor Performance is not set to Highest.

 

[jusi]

Thanks so much for your suggestions. A thermal calibration is the one thing I haven't done. I've pretty much ruled out anything actually overheating cause I can feel that there isn't too much heat circulating around in there. Even when I point an outside fan through the front grating, the fans keep going so I think there must be a sensor issue perhaps...

I will look into the thermal calibration and let you know how it goes.

Many thanks again,
j

 

[jusi]

wow! didn't realize how hard it would be to get the ASD discs...!

 

[jusi]

so after finally acquiring the correct ASD discs for my machine, i booted and ran the open firmware (OF) tests which all came out with no problems but when i tried to boot into the OS diagnostic it just crashed out. THEN i see in the diagnostic manual that the OS diagnostic is not supported for the late 2005 Quad G5!!

does anyone know if/how to run a thermal calibration on a late 2005 quad G5???? anyone???

-- these fans are seriously loud ALL day!

 

[regis.redj]

you can find ASD 2.6 using peer to peer tools

I have spend a lot of time trying software ( including thermal calibration) but issue was with the LCS.

For fan issue, I solve this by washing the waterblock ( not easy and time consuming) and replace coolant liquid.

Régis