1 2 Previous Next 21 Replies Latest reply: May 30, 2008 3:57 PM by dp345_123
PrimalEyes Level 1 Level 1 (0 points)
So for a week or so now my Macbook Pro has been making a faint purring noise on the right side. It hasn't been functioning any differently in any way. I brought it to the Apple store, and after running a lot of hardware checks said it looked fine. Has anyone else heard of a MacPro... purring?

Fujitsu Lifebook, Mac OS X (10.5.2)
  • 1. Re: Macbook Pro Purring?
    MisterChrister Level 1 Level 1 (0 points)
    there are many threads on this. look around
  • 2. Re: Macbook Pro Purring?
    S.U. Level 6 Level 6 (8,360 points)
    It sounds like you might be hearing the right fan rubbing on the case or on something. You might try processor intensive activity and see if the sound changes as the fan speeds up. As long as both fans run at about the same speed, there is probably no real problem. But keep an eye on it. The added friction could cause premature wear, and you might want to have it replaced before the warranty runs out.

    Good luck!
  • 3. Re: Macbook Pro Purring?
    dp345_123 Level 1 Level 1 (15 points)
    I occasionally have the same issue. I figured out that the sound can also come from the hard drive. Since the case is so thin, you will hear normal operating sounds...
  • 4. Re: Macbook Pro Purring?
    David Dellinger Level 2 Level 2 (165 points)
    Hi,

    My wife's 15" MacBook Pro 2.16 GHz also exhibits this type of noise.
    I wouldn't have thought to call it purring exactly, but yeah, that's what it is.
    It's also getting really hot underneath.
    The system is just over a year old, but luckily, we have AppleCare.

    She has taken it to the local Apple Store twice and they can't find any problem.

    I'll check the fan speeds to see if that's a problem. (using smcFanControl)

    David
  • 5. Re: Macbook Pro Purring?
    S.U. Level 6 Level 6 (8,360 points)
    It would be best to disable smc fan control and see what the fans do on their own. Also run the Apple Hardware Test and look for an error code. If it is getting hot underneath, it sounds like the fans may not be spinning fast enough to keep the computer cool. SMC Fan Control may be masking an underlying problem.

    Also, open Activity Monitor and set it to "All Processes" on top and select the CPU on the bar below. Then look for any runaway process which is hogging the CPU. If you find one, quit it and see what the fans do. A runaway process will hog the CPU and make the processor be very hot, and the fans should be running all out to cool the computer. If they are not, then there's a problem.

    You can also install iStatPro if you haven't already and check the actual temperatures and fan speeds without smc fan control.

    Good luck!
  • 6. Re: Macbook Pro Purring?
    Courcoul Level 6 Level 6 (11,470 points)
    1) On the 15in MBP, the HD is on the LEFT side, right under the palm rest, but regardless, when an HD starts making any sort of purring noise it is time to start backing things up and arranging for a replacement. Put your ear right there and try to determine if this is indeed the origin of the sound. Maybe put it to sleep with the lid open, place your ear and then tap a key to wake it up and listen as the drive spins up.
    2) Since the Superdrive is on the RIGHT side, are you sure you didn't forget a CD/DVD in there?
    3) *RANT ON* For the life of me, I cannot understand why people would have the presumptuousness of thinking they can outsmart the engineers who designed a very complex product and go about bypassing important safety features such as the fan speed control, then complain when hit with system failure. *RANT OFF*
  • 7. Re: Macbook Pro Purring?
    David Dellinger Level 2 Level 2 (165 points)
    Hi,
    Thanks for the info.
    The noise sounds more like a fan than a disk or a optical drive, but I could be wrong.
    There's nothing in the optical drive.
    The noise emanates from the right side, near the screen hinge.
    I'm not trying to change my wife's system. I'm trying to troubleshoot it, since the Apple Geniuses don't seem to want to do that when we take it in. They can't hear the problem, and don't seem to think that it overheats. I'm just looking for ideas of more exact information to tell them the next time I take it in for repair.
    David
  • 8. Re: Macbook Pro Purring?
    David Dellinger Level 2 Level 2 (165 points)
    Hi all,

    I'm first now getting a chance to look at her computer.

    Actually, listening to the sound again, the fan sounds more like a geiger counter in the center of a uranium mine. When the fan speeds are at 2000 rpm, the sound isn't very loud. There are other noises in the house this morning, so I have to put my ear up to the DVI port to really hear the noise. When the fan speed rises to even 2500 rpm, then it's more noticeable.

    When I have Chess.app play itself at the hardest level (and them duplicate the app and have that new app do the same, since Chess.app only utilizes one core), the temperature levels go up and the fans spin faster.

    Both fans revolve at approximately the same speed.

    David
  • 9. Re: Macbook Pro Purring?
    Courcoul Level 6 Level 6 (11,470 points)
    Actually, listening to the sound again, the fan sounds more like a geiger counter in the center of a uranium mine.

    In all, that is good news. Since it isn't the HD, at least the data is safe for now. The noise is either the fan scraping against its housing, maybe due to dust buildup, or the shaft bearings on the fan motor are shot. Either way, servicing requires cracking the computer open and probably replacing the part (if dust, the fan may be salvageable). This is best left to trained personnel at an Apple Store or an AASP, since the Mac is still under warranty. Your job now is to persuade them to do so.
  • 10. Re: Macbook Pro Purring?
    S.U. Level 6 Level 6 (8,360 points)
    I understand that you don't want to change your wife's system, but one question is, why was smc fan control installed in the first place? Was it because there was some sort of fan or cooling problem? If so, you need to at least temporarily disable the smc program and see what the underlying problem is. And if you run the AHT with smc off and get an error code, then you will have something very specific to take to Apple. And it may well be they can't hear anything in a noisy Apple Store. If you need to, see if you can record it and play it louder for them or something.

    Good luck!
  • 11. Re: Macbook Pro Purring?
    David Dellinger Level 2 Level 2 (165 points)
    Hi,

    I actually hadn't installed smc fan control yet... I had only heard about it as a way to see the fan speed (through another thread). I installed istatpro instead.

    Good idea about recording the sound. I did think of that too. I'll probably do that and take it to the Apple Store tonight or tomorrow.

    Thanks for your help.

    David
  • 12. Re: Macbook Pro Purring?
    David Dellinger Level 2 Level 2 (165 points)
    Hi again,

    What's AHT? Is that the Apple Hardware Test program? I haven't run that yet, but will do so. Thanks.

    Does the SMC fan control actually change the firmware? I know that SMC has to do something at the lower level, since I've seen the SMC firmware updates, but didn't know that the SMC fan control would leave anything behind after it stopped running.

    Also, there was/is a cooling issue as well. My wife has been complaining for a few weeks that her laptop was getting hotter than normal.

    David
  • 13. Re: Macbook Pro Purring?
    S.U. Level 6 Level 6 (8,360 points)
    Yes the AHT is the Apple Hardware Test. Run the extended version.

    I have never run SMC Fan control, so I don't really know what it does. But I think it lets you set the speed of the fan manually instead of letting it be set by the thermal sensors. But I don't know why you would want to do that, because if the fans are not working properly to cool the Mac, then there is a problem somewhere that needs to be diagnosed and fixed. Especially while the Mac is under warranty.

    Use iStatPro to check on just what is getting hot. Also carefully check the battery to see if there is a problem with it. And as I suggested earlier, use Activity Monitor to check for any runaway applications, especially if CPU usage seems too high.

    Good luck!
  • 14. Re: Macbook Pro Purring?
    David Dellinger Level 2 Level 2 (165 points)
    Hi,

    Thanks for the info, and for the encouragement.

    I recorded the sound last night using my iSight connected to my Mac Mini with the Amadeus audio editing program. Actually, I recorded the sound coming out of the right side when istatpro reported the rpm to be 2000, and also when it was 4500. I can still hear the noise when the RPM is at 4500, but it isn't proportionally louder. Actually, I hear the noise in the background, but it sounds almost as if it is the same level no matter which speed the fan spins at, so maybe it's not be a fan issue at all. I have an 11am Apple Genius appointment this morning, so will talk to them about it, and let them listen to the sound.
    I did notice that the sound starts during the boot process, at precisely the same moment that the screen goes from grey to blue.

    My MacBook Pro from work, with exactly the same specs, doesn't make any noise at all. That's how my wife's computer used to be.

    Wish me luck.

    David
1 2 Previous Next