Macbook won't fan automatically

Discussion in 'MacBook' started by freems, Apr 14, 2012.

  1. freems macrumors newbie

    Joined:
    Apr 14, 2012
    Location:
    Denmark
    #1
    Hello, I've had my Macbook for about 1.5 years now and it's been a real bitch lately because the fan doesn't seem to register the heat properly.

    I discovered the problem when the computer was burning to the touch but I could hear that the fan was on a low RPM.
    I installed SMC Fan Control and with it I could see that the temp was at 86.

    It still wouldn't fan so I manually changed the minimum RPM to 5000 to lower the temp. It works but so far I've had to constantly keep an eye on the temperature and the RPM. It's a hassle and if anyone out there has encountered a similar problem then feedback would be the greatest thing.

    Thank you.
     
  2. east85 macrumors 65816

    east85

    Joined:
    Jun 24, 2010
    #2
    This might not be the end all solution for your problem, as I'm sure some more literate mac users will be able to fill you in on the solution to your problem but it might be helpful to use Activity Monitor to keep an eye on which programs tend to spike your CPU in the meantime. It would be much easier if you knew which programs were running that would require you to up the speed beforehand (you could possibly avoid using them). Probably better for your computer as well. Flash is also very good at spiking your CPU and working your computer harder, you may want to install a flash blocking plugin on your browser in the meantime.

    http://clicktoflash.com/ - Safari
    https://addons.mozilla.org/en-US/firefox/addon/flashblock/ - Firefox
    http://www.chromeextensions.org/appearance-functioning/flashblock/ - Chrome

    Sorry I couldn't provide you with an end all response, but I'm sure some courteous users on here with more knowledge will be able to point you towards a more permanent solution. Good luck.
     
  3. Intell macrumors P6

    Intell

    Joined:
    Jan 24, 2010
    Location:
    Inside
    #3
    If the fan speed changes manually, then there isn't anything wrong with the fan itself. Macbooks do run hot and their fan does rev up when needed. Does yours rev up at all or does it just turn off due to overheating?
     
  4. freems thread starter macrumors newbie

    Joined:
    Apr 14, 2012
    Location:
    Denmark
    #4
    It won't rev up at all. That's why I have to manually rev it with SMC otherwise it would overheat.
    It's like the fan won't register that the laptop is in fact very hot.
     
  5. Intell macrumors P6

    Intell

    Joined:
    Jan 24, 2010
    Location:
    Inside
    #6
    Does it overheat and turn itself off? Unless it's done that, it's still working as it should.
     
  6. freems thread starter macrumors newbie

    Joined:
    Apr 14, 2012
    Location:
    Denmark
    #7
    It didn't overheat because I made stopped it before it got to that.
    It was running on 86. 86! I know it shuts down at 90 but it's not supposed to ever get that close. And I wasn't doing anything with my RAM, I was just browsing the internet.

    I've tried resetting the PRAM and SMC and all that, but it still won't rev above 2000 RPM no matter how hot it gets.

    It's making me go nuts!
     
  7. GGJstudios macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #8
    No, it doesn't shut down at 90. The Intel processors used in Macs are designed to automatically shut down to prevent damage if they truly overheat. CPU Tjmax = 105C, GPU Tjmax = 100C on i3, i5, i7 processors. (Source: Intel)
    PRAM/NVRAM has nothing to do heat/fan/power issues. Resetting it will not help. Only resetting the SMC addresses such issues.
    Unless there is a rare defect in a Mac, most temps are well within the normal operating range, considering the workload being put on it. Websites with Flash content, games and other multimedia apps will put higher demand on the CPU/GPU, generating more heat. This is normal. If you're constantly putting high demands on your system, such as gaming or other multimedia tasks, expect temps to rise and fans to spin up accordingly. It's just your Mac doing its job to maintain temps within the normal range.

    It is also quite normal for your Mac to become extremely hot to the touch during intensive operations. The aluminum body transfers heat more effectively than other materials used in computer casings, so you will feel the heat more. This doesn't indicate that it's overheating and will not harm the computer to be hot to the touch.

    Your fans are always on when your Mac is on, spinning at a minimum of 2000 rpm (for MBPs) or 1800 rpm (for MBAs, MBs and minis). iMacs have 3 fans with minimum speeds in the 800-1200 range. They will spin faster as needed to keep temps at a safe level. If they're spinning up without increased heat, try resetting the SMC. (PRAM/NVRAM has nothing to do with these issues, so resetting it will not help.)

    The intake and exhaust vents are in the back of the computer near the hinge on all Mac notebooks. The iMac vent is a slot on the back near the top of the computer. Make sure the vents remain unblocked to allow your computer to perform at its best.

    Learn about the fans in your Mac
    Apple Portables: Operating temperature

    For Flash-related issues:
     
  8. Intell macrumors P6

    Intell

    Joined:
    Jan 24, 2010
    Location:
    Inside
    #9
    Try just letting it overheat. If the fan never comes on, the you should call the Apple Store.
     
  9. freems thread starter macrumors newbie

    Joined:
    Apr 14, 2012
    Location:
    Denmark
    #10
    Thanks for the thorough answer!
    I adore my Macbook and it's a huge part of my life as both as student and a person who uses a computer. Before I encountered this problem, the fan would kick in violently at just 75 degrees, but now it doesn't move above 2000 at all. That's a change in behaviour and I preferred how it behaved before. It's eerily silent.
     
  10. GGJstudios macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #11
    Follow Intell's suggestion and just run your Mac normally. See if it shuts down. If it does without the fans spinning up, take it to Apple. Remember, your fans may not spin up when temps spike higher, but they may when high temps are sustained for some period of time. Unless something is defective or damaged, your Mac will manage temps and fans quite well, without any involvement or interference from the user or 3rd party apps.
     

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