4 Replies Latest reply: Jan 22, 2009 9:43 AM by rkaufmann87
fki Level 1 Level 1 (0 points)
I've had an Intel-Based iMac for over a year now, and I've had this problem since nearly then. Random times when the computer is on, no matter what process are being performed, the computer will start to make a really loud fan noise coming from the top area of the computer and blow air out of the back top vent. It is nearly impossible to stop-- it will cease momentarily if the computer is put into sleep and brought back; however, even then it will just continue to make the sound once again. Does anyone know what is causing this problem and how to fix it? Thanks.

Intel Based iMac, Mac OS X (10.5)
  • 1. Re: iMac Fan Noise-- Will Not Stop
    rkaufmann87 Level 8 Level 8 (42,145 points)
    If your machine is still under warranty or you have AppleCare you should ask Apple to help you out. However before doing that do a SMC and PRAM reset, here are the instructions:

    1. Turn off your iMac and unplug everything from it for 30 seconds.

    2. Plug in the power cord, keyboard and mouse only.

    3. Press the power button and immediately hold down the Option, Command, P & R keys until you hear the second gong then release the keys. Your machine will start up normally, then check for the issues you are having.
  • 2. Re: iMac Fan Noise-- Will Not Stop
    Carolyn Samit Level 10 Level 10 (89,655 points)
    Hello and Welcome to Apple Discussions ...

    Try resetting the System Management Controller: http://support.apple.com/kb/HT1543
    Summary
    The System Management Controller (SMC) is a chip on the logic board that controls all power functions for your computer. If your computer is experiencing any power issue, resetting the SMC may resolve it. The SMC controls several functions, including:

    Telling the computer when to turn on, turn off, sleep, wake, idle, and so forth.
    Handling system resets from various commands.
    *Controlling the fans.*

    Try booting in Safe Mode:

    Starting up in “safe mode” may help you to diagnose problems you’re having with your computer.

    To start up in safe mode:
    Shut down your computer and wait 10 seconds.
    Press the power button.
    Immediately after you hear the startup tone, hold down the Shift key.
    You should press the Shift key as soon as possible after your hear the startup tone, but not before.
    Release the Shift key when you see the gray Apple logo and progress indicator (spinning gear).
    To leave safe mode, restart the computer normally without holding down any keys during startup.

    Run the Apple Hardware Test: http://support.apple.com/kb/HT1509




    Carolyn

    Message was edited by: Carolyn Samit
  • 3. Re: iMac Fan Noise-- Will Not Stop
    toyotag Level 1 Level 1 (0 points)
    I too have had this problem since purchasing my iMac in June of 2008. While under the 90 day complimentary warranty, a certified technician came to my house (twice) replacing both the CPU fan and the CPU controller board. This worked for a short while, but after about two weeks the problem resurfaced. I just lived with the problem until November when I couldn't handle it anymore, so I called Apple again, and they wouldn't help me unless I signed up for the extende "Apple Care" plan since I was outside the 90 day period. Refusing to spend more money on an inherant manufacturing defect, I continue to use this computer, irritating as the fan noise is.

    I have tried resetting the PRAM, SMU, reloaded the operating system, reloaded secondary software, like printer drivers, Firefox, etc. and still no luck. It's so frustrating that I will most likely revert back to a PC after this computer dies. Reading over all the problems people experience with Macs, I'm having second thoughts about my decision to purchase one. I have even decided not to buy and iPhone, not wanting to go through this again.

    If you can take your computer in and get it fixed, do so. If you're succesful, let me know what the problem was...Please!
  • 4. Re: iMac Fan Noise-- Will Not Stop
    rkaufmann87 Level 8 Level 8 (42,145 points)
    toyotag,

    I think you misunderstood Apple, they won't do telephone support after 90 days unless you purchase AppleCare which I strongly recommend you do! However you are covered for 1 year for all manufacturers defects. In the event you decide to pass on AppleCare you have a couple of choices first take your machine into a Apple store or any authorized dealer second pay for telephone support and arrange getting your machine repaired.

    Before doing the above I would recommend doing a SMC and PRAM reset. Instructions for this are:

    1. Turn off your iMac and unplug everything from it for 30 seconds.

    2. Plug in the power cord, keyboard and mouse only.

    3. Press the power button and immediately hold down the Option, Command, P & R keys until you hear the second gong then release the keys. Your machine will start up normally, then check for the issues you are having.