fan runs constantly?

Discussion in 'MacBook Pro' started by goosed88, Oct 20, 2009.

  1. goosed88 macrumors newbie

    Joined:
    Oct 20, 2009
    #1
    I've got an early 2008 Macbook Pro and, recently, I've noticed that the fan (fans?) begins running from the moment the computer is powered-up. iStat tells me that both fans are running at about 2000 rpms, though I only hear a slight whoosing noise from the left side. I don't remember the fan running constantly, and I have noticed that my battery life seems worse than normal recently. Is this normal, and something I just haven't noticed until recently?
     
  2. pdubak macrumors member

    Joined:
    Oct 20, 2009
    #2
    You can try resetting the SMC, disconnect the power adapter and battery and hold the power button for 5 seconds to reset. Reconnect your power and boot.

    If you still have the problem:

    Your fans are always running, you just shouldn't hear them most of the time because they're running at a low RPM. The fan speed is based on temp. sensors and they speed up when things get warm. For safety, if one of those temp sensors fails or the cable comes loose, the fan will run at full speed right from turning on (assuming already "cold"). The apple store or service center can diagnose faulty temp sensors and runaway fans if this is the case. The temp. sensor parts are usually pretty cheap but there's always a possibility something else isn't working correctly.
     
  3. goosed88 thread starter macrumors newbie

    Joined:
    Oct 20, 2009
    #3
    Thanks for the reply - I had actually tried the reset before, which didn't seem to make a difference. If the fans are designed to run constantly, does anyone know what speed they should run at for a "cold" system that was just turned on? I don't live particularly close to any service centers, so it'll be an effort to get out to one.
     
  4. J the Ninja macrumors 68000

    Joined:
    Jul 14, 2008
    #4
    2000rpm for both fans is the normal idle setting.
     
  5. macbooker15 macrumors 6502

    Joined:
    Jan 19, 2008
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    #5
    On the white macbooks its at 1800 rpm. My base is around 2300 rpm set with FanControl because it got way too hot.
     
  6. deltaiscain macrumors regular

    Joined:
    Jul 24, 2008
    #6
    Try using iStat to check your CPU temperature. If there isn't a CPU field, then you sensor failed, like in my case. Fans will never go off of the max, there are ways to limit the max fan speed. I'm out of warranty, so I did that.
     
  7. kryptonianjorel macrumors 6502

    Joined:
    Jul 3, 2009
    #7
    I use smcfancontrol to control my fans. 2000rpm is the base speed. I usually run mine at 4000rpm, and that keeps it mighty cool
     

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