Troublesome whirring sound.

Whitehill

Whitehill

Registered
One of my iMacs has started making a whirring sound infrequently. The machine summary is down below. Once the sound starts, it stays on. The only way I have discovered to stop the whirring is to power off the machine, then start it up.

I checked the logs via Console and saw no unusual activity or messages. The Activity Monitor also shows nothing unusual.

The sound is not as intense as CD/DVD activity, but something like it. If this was not an iMac, I would guess that a fan was trying to die.

Any words of wisdom? I have Techtool Pro 6 on another iMac, but I don't know if my license allows me to use it elsewhere.

Model Name: iMac
Model Identifier: iMac9,1
Processor Name: Intel Core 2 Duo
Processor Speed: 2.66 GHz
Number Of Processors: 1
Total Number Of Cores: 2
L2 Cache: 6 MB
Memory: 4 GB
Bus Speed: 1.07 GHz
Boot ROM Version: IM91.008D.B08
SMC Version (system): 1.44f0
 
You have three fans in your iMac.
You can turn up each fan individually, using a utility like smcFanControl.
That will quickly tell you if you have a fan with mechanical problems. Or, just a fan doing what it's designed to do (trying to keep your system cool!)
 
jbarley said:
You think the fans in your iMac are immune to problems?
Click to expand...

No, but I can't recall ever hearing them before, even earlier this summer when the temp hit the upper 90s in my house with no A/C. So far as I know, this has now happened twice, both times in 70-ish temps.
 
Use smcFanControl. That's how I diagnosed mine, thanks to DeltaMac.

My MBP's right fan went out suddenly a week or so ago. Bought replacement & installed it myself. If I can do a MBP, an iMac should be easy.
 
I installed smcFanControl on 9/21 and everything was quiet until this morning. Here is what I saw:
Code: 
       20" iMac |  24" iMac
--- | --------- | ---------
Fan |  RPM Temp |  RPM Temp
HDD | 1600   82 | 1200  105
ODD | 1350   82 |  700  105
CPU | 1200   82 | 1200  105
Again, with a restart, the sound went away, but the speeds and temps didn't change. For comparison, I added above on the right the numbers for my other iMac.
 
Just a reminder - smcFanControl is not just a monitor app. You can manually run up each individual fan to max, or some other speed. That will quickly help you decide if that noise is caused by a fan, and which fan is the culprit.
Just for fun, check the small round air intake on the back of your iMac, directly above the power connector. That will sometimes get clogged, and very little air gets through.
 
You must log in or register to reply here.
Back
Top