Defect Poll, Unibody MBP: Fans Make 'Grinding' Noise at Min RPM w/ Base @ 45º Angle

Discussion in 'MacBook Pro' started by dcMobile, Dec 22, 2008.


Do your Late 2008 MBP fans 'grind' at min speed w/ base @ 45º angle?

  1. Yup--I can hear it clearly in that 40º-50º sweet spot.

    5 vote(s)
  2. Nope--the fans are practically silent at minimum speed no matter how I tilt it fore and aft.

    8 vote(s)
  1. dcMobile macrumors member

    Jul 16, 2007
    Hey Late 2008 MBP Owners...

    I tend to use my MBP in bed a lot, propped up on my thighs at about a 45º angle, and I've noticed a grinding noise from the fans when using it this way.

    I've just learned that this grinding noise is not a result of case compression, as even if I lift the machine up by the sides and rotate it fore and aft in space, there's a 10º zone (between 40º and 50º approximately) that the fans make a distinct grinding sound.

    Note that, for me anyway, this will only happen between minimum fan speed (1990 rpm) and ~2300.

    Let me know what you guys find. Be sure to put one ear a few inches away from the hinge area when you test!
  2. MICHAELSD macrumors 68040


    Jul 13, 2008
    It's definitely there for me. I don't really consider it a problem, though, since I never use my MacBook Pro that way.
  3. J the Ninja macrumors 68000

    Jul 14, 2008
    Nope. Just tried rotating mine from flat on my desk to 90 degrees. Aside from almost getting hit in the face by the NEW Easy-To-Operate-Hinge and the NEW Screen-Covered-In-Really-Heavy-Glass conspiring to make the NEW Flops-Over-From-Its-Own-Weight-Like-A-Baby's-Head lid, everything was fine. No noise.
  4. xpovos macrumors 6502a


    Jun 7, 2007
    My fans were doing the same. The left fan was especially offensive. Sometimes tilting wasn't even necessary as it would grind/rattle even when flat on a table, but the noise got much louder as the laptop tilted.

    I had both cooling fans replaced under warranty and have had no such fan noise ever since.

    (Of course, I now have the low-brightness 9400M flicker that probably requires a logic board replacement.)
  5. darrenscerri macrumors regular


    Nov 15, 2007
  6. raviliousness macrumors newbie

    Dec 15, 2008
    Reading, UK
    No no change in noise at 40-50 degrees.

    Although the left fan has had a continuous (fairly quiet but noticeable) high-rate ticking sound at 2000rpm ever since playing some games with the fan up high at around 5000rpm.

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