Fan whirr, 75% idle and 5300rpm -- help!

Discussion in 'MacBook' started by radicaldog, Jun 17, 2010.

  1. radicaldog macrumors member

    Joined:
    Mar 1, 2010
    #1
    The title says it all: low CPU activity, and yet the fan whirrs like crazy, and I guess the exhaust fan rpm figure is too high. What's wrong with my trusty BlackBook? Could it be due to the fact that I upgraded to a 320Gb HDD?

    Thanks in advance for your help.
     
  2. spinnerlys Guest

    spinnerlys

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    Sep 7, 2008
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    #2
    Use iStat Pro or iStat Menus to see the CPU and HDD temperatures?

    Have you tried an SMC reset?
     
  3. radicaldog thread starter macrumors member

    Joined:
    Mar 1, 2010
    #3
    Slightly different conditions now, after watching a couple of minutes of video: loud fan, no whirr, 87% idle, 6100 rpm, 37c HDD, 64c CPU, heatsinks in the mid-fifties. What's the prognosis?
     
  4. spinnerlys Guest

    spinnerlys

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    #4
    Have you reset the SMC yet?

    64°C shouldn't let the fans spin that high. Have you installed any fan control software?
     
  5. radicaldog thread starter macrumors member

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    Mar 1, 2010
    #5
    Will try the reset tomorrow. Recommended fan control software?
     
  6. spinnerlys Guest

    spinnerlys

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  7. Pax macrumors 6502a

    Joined:
    Dec 12, 2003
    #7
    You might have a faulty internal temperature sensor. If the Mac detects no reading from a sensor it can go into fail safe mode where it runs the fans at full speed.

    Run Hardware Test (on the install DVD). That will show up any faulty sensors. Sensors are quite cheap to fix.

    edit: I would not install fan control software yet. I think you may have some kind of problem. IMHO you should try and resolve the problem rather than just masking it with fan control software. Otherwise you might cook some internal component.
     
  8. radicaldog thread starter macrumors member

    Joined:
    Mar 1, 2010
    #8
    SMC reset did nothing. Might have to take it to an Apple centre. Hope they don't charge me just to look at it.
     
  9. Pax macrumors 6502a

    Joined:
    Dec 12, 2003
    #9
    You might want to take a look at this thread - very similar symptoms
    http://forums.macrumors.com/showthread.php?t=954136

    What are your temps and fan speed at idle ie all programs closed, Activity Monitor showing <2% CPU?

    If your fan always runs at 6200 rpm that's the symptom of a bad temperature sensor. But from your earlier post it seems to vary from 5300 up to 6200. Therefore I don't think it's the temp sensor (sorry, I should have read your post properly).

    Could you post all your temperatures when the fan is at 6200 rpm? You can take a screenshot of iStat and post it here. (reason - it's possible that some other component is hot & the fan is working to cool that. Your HDD is warm but not amazingly so).

    Blocked air path? When the fan is at 6200 rpm, you should feel a strong air flow out of the hinge.
     

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