Mac Question

I have a Dell in the office, and at home, I have a G5 iMac — ita about 2 years old, and it is the pre-Intel line (Motorola chip), with a 1.5G of ram.

Anytime I "push it" — run a lot of apps at once, or any video or iTunes music, the internal fan spools up. It sounds like a 747 at JFK waiting for takeoff clearance. (Safari is an entirely different disaster, generating a spinning beach ball whenever I have a few windows open).

Its been like that since day one, and ts beginning to drive me a bit batty . . .

Any ideas about how easy it is to swap this out? Is this an ordeal, or can I do it myself (I’ve swapped ram and hard drives in the past)

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  1. angryinch commented on Jan 31

    I have the same problem, though generally the Mac works great, best one I’ve even run.

    As far as Safari, I’ve stop using it completely for the reasons you cite. I’ve moved to Firefox with no problems at all and it is now my default browser.

  2. Glenn Fleishman commented on Jan 31

    Mac tech journalist here — been using Macs since 1985, writing about them since 1990-odd.

    There’s something terribly wrong here, and if this was happening from day one, it’s too bad you didn’t get it repaired under warranty. The iMac model you have can occasionally make fan noises, but it should never be anywhere near as loud as you describe. It was probably always defective.

    Did you purchase AppleCare for extended warranty? I rarely recommend AppleCare (which provides 3 years of labor, parts, and phone support) for desktop models, as the price isn’t worth it. It’s always worth it for laptops. Every single Apple laptop I’ve owned has gone back for repair in their first three years! (But each time, the problem was fixed rapidly without any complaints about using the warranty by Apple, so there’s that in their favor.)

    The fan is not something you want to swap out yourself as far as I can tell. You might be able to find a Mac repair shop online that could order the part and do it for you. Apple also performs paid repairs, and they might be willing to handle it. (If the part is defective, they might even eat it if you write a letter explaining it; it’s happened before.)

    Another idea: Reinstall OS X. Don’t wipe the drive, but use the Archive and Install option which preserves all your user files and settings, and installs a new version of the OS from scratch. Then run all the updates. The fan is controlled via software, so there’s a possibility that something (cosmic rays?) went wrong in the operating system.

    As for Safari, it sounds like you’re using an old, buggy version, or there could be a problem with the processor.

    You might have a lemon.

  3. wnsrfr commented on Jan 31

    If you google “imac g5 noisy fans” in either or regular google, you will get a LOT of hits…

    In the PC world, you can easily buy aftermarket fans for both your case and CPU from places like and other “build it yourself” vendors. I have a PC I built myself and bought both a quieter CPU fan as well as an additional case fan when my fan noise bothered me…

    I kind of ran-out of helpful-guy time researching, trying to find simple fixes, but found this article, which I think is probably the MOST PRACTICAL…

    You can make it a bit more stylish by picking a fancy fan from a place like newegg, they really have some cool ones, neon is there but no spinning hubs…gamers like fancy fans!

    You can also look around for an aftermarket case fan that can possibly replace the Apple one that is quieter and more powerful…generally the case fans are quiet and it is probably your CPU fan that is creating the biggest ruckus, and those are hard, and scary, to replace…so you want to BOOST your case cooling, and then that sweeps the cooler air through and keeps your CPU fan from taking off.

  4. Fred C Dobbs commented on Jan 31

    Sorry to hear of your fan problem. I too own a Mac (I bought about the same time as you) and my fan
    “reved-up” like it was a plane, taking off, a few times, but after reinstalling the OS, I have not had a problem in the 2+ years since. Good luck!!!!

  5. Uncle Jack commented on Jan 31

    I moved my Powerbook to Firefox for Mac. Easier tab browsing and no spinning beach ball of death.

  6. Robert Coté commented on Jan 31

    Mac tech here. The very first thing is to blow out the box. A small bit of dust in the wrong place could be the problem. None of this “can of air” stuff, I’m talking air compressor and caution. Then there’s “Firmware” and SMU issues. Here’s a general search return:
    Those include DIY fan replacements but I particularly noticed; which documents possible fan overruns. The other mention of a buggy Safari release also rises high on my list. It isn’t easy to do just a Safari install so a new 10.4.x install is the fallback answer.

    Clean, firmware, SMU, OS clean install in that order. Bon chance.

  7. Aaron commented on Jan 31

    This is a common Apple problem. The solution is pretty straight forward. Get rid of the PCs.

  8. David Yaseen commented on Jan 31

    Dealt with this exact issue on my gf’s iMac G5. The problem began intermittently, and was then a constant presence from about :20 after she booted it. It’s a faulty motherboard (temp sensor) what’s causing the issue. If you don’t have Applecare, it will cost more than the machine’s worth to fix. Buy an intel model; it will be a lot faster, and fan noise is not generally a problem. winsfr’s solution is clever, if not elegant.

    If you do have Applecare, drop it at an Apple store and they’ll take care of it.

    It’s so nice giving computer advice to someone for whom money is not an issue for a change!

  9. bharat commented on Jan 31

    not a whole lot u can do.. its doing that because things are backed up in the processor que.. and its runnin the fans to keep it cool cuz its HAULLING!

    Get the intel!

  10. David Andrew Taylor commented on Jan 31

    Although I’ve never owned that particular Mac, I can tell you that there is something wrong with the fan in general from experience with knowing people owning that Mac. Getting the fan replaced is fairly simple. You can easily take it to a second hand store and have them do it for you in less than a day. But, no matter what, it sounds like you’ll need to yank out that fan.

  11. Bryan commented on Jan 31

    Have you tried resetting the SMU? Shut your iMac down, then unplug all cords (including the power cord). Wait five minutes then power the computer back up.

    Here is an apple support article.

    Sometimes this fixes the racing fan issue.

  12. mdr commented on Jan 31

    Let me amplify one comment from above — get rid of Safari, and switch to Firefox. Infinitely better. It never gets hung up or crashes.

  13. Tom Miller commented on Jan 31

    I have a G5 iMac and I have exactly the same problem–a loud racing fan. I also have both Safari and Firefox and it races with both–especially when I have streaming video or sound.

    I had a G4 iMac–the one with the white globe–and after 2 years the screen suddenly went black and I didn’t have AppleCare. I was able to pull the hard drive but basically the machine is junk–$1800 for 2 years of use!?!?!

    I wouldn’t buy an Apple product without Apple Care.

  14. Kris Tuttle commented on Jan 31

    Don’t upgrade old iron.

    Buy a new machine.

  15. albrt commented on Jan 31

    I have the same vintage and also had the motherboard burn out as did the commenter above. I bought the extended warranty so they replaced the motherboard, but they also put in a fan that is EVEN LOUDER than the original. My only advice is to be careful about replacing the fan because that motherboard apparently needs major cooling assistance.

    Firefox is much better than Safari.

  16. jjr commented on Jan 31

    I would recommend that everyone factor the cost of extended Applecare into the price of an Apple box, laptop or no. One incident and it’s paid for itself, and I have seen enough issues with Apple desktop systems to believe that you have a better than 50:50 chance of seeing one within 3 years.

    I run Firefox and Safari side-by-side, and I have tended to pick up on which sites work best with which browser. Firefox is far from perfect. Safari has a much cleaner Java/Javascript implementation. Firefox has a problem shutting down, wherein I have to shut it down twice to force it to quit.

    I also think that Safari handles embedded audio/video/flash better, but I also use flashblock and adblock plugins under Firefox which can cause all sorts of problems with legit flashys. Anyone else peeved that formerly perfectly good sites like yahoo maps have coverted over to flash and gummed up the works?

    Another advantage of using two browsers like this is that I can simultaneously login to two different instances of gmail/ebay/yahoo/etc.

  17. jjr commented on Jan 31

    I also neglected to mention the memory leaks in Firefox that don’t become apparent until I’ve had the computer on for a couple of days and Firefox open the whole time. I’ve taken to trying to shut down the system and/or killing my browser and restarting daily. Safari does not have nearly as apparent memory leaks. If I don’t take preventative measures, I can almost predict when Firefox is fixing to crash, as it gets unresponsive and has a terrible time swapping in from another task.

  18. wnsrfr commented on Jan 31

    Not elegant? Maybe not pretty, but in the engineering sense, very elegant!

    For one simple reason–Apple engineering for these one piece Macs leaves barely enough room inside for a finger nail clipping let alone an additional fan…the only answer is a bolt-on, and like I said, you can get one with cool neon, like on a tuner car :)

  19. Bob A commented on Jan 31

    Cpu cooling fans for a pc swap out easily and cost about $10 and are usually the culprit. Power supplies which also have a fan cost about $50 and are easily replaceable. Look inside and see if there’s a fan clipped on to the CPU. If so you ought to be able to get a replacement. But I don’t see any available on Macmall. Silly that they would make it hard or expensive when it doesn’t need to be.

  20. Roger Bigod commented on Feb 1

    It could be that it’s running the way it’s supposed to. I have a G5 with the Motorola chips, and the fan gets louder with more CPU usage. You can watch this on the Activity Monitor utility. If a video is using close to 100% of CPU, the fan will be at the max that the thermal sensor is set for.

    I had a major problem with the fan occasionally revving up to the max with no CPU activity. The Applecare people walked me through a procedure to reset “parameter RAM” and when that wouldn’t work, they sent out a tech to install new CPU’s. There was a short delay getting proper software to recalibrate the thermal sensor for the fan, but now everything is copascetic. All on their dime.

    The thermal calibration software is proprietary and required some mumbo-jumbo between Apple and the techs who came out. I don’t think that’s your problem, if the sound has been at this level since day one. Before it was fixed, my fan went to a fairly high level and stayed there.

    Based on this, three suggestions: clean up any dust and gunk that might be interfering with the ventilation. Probably not effective, but low cost. Second, look in the instruction book or Google the parameter RAM check. You just restart with some special keys held down, although from the sound of it your machine could be performing to spec. Resetting doesn’t damage the file system (although backups are always good juju), but check that it doesn’t mung anything important. And get Applecare with the next machine. I’ve never had an unsatisfactory call to them.

  21. rob commented on Feb 1

    Seriously, buy a new Intel Mac. They’re sweet. They run faster and cooler. Definitely switch to Firefox. The Setup Assistant will transfer your old files to the machine quickly and easily.

    I bought my wife a MacBook (one of the first Intel versions). It’s amazingly fast. It makes my Powerbook G4 look pathetic.

    PS: You’ll be helping that first quarter consumer spending number…

  22. Heather commented on Feb 3

    Try dusting or air canning the vent at the bottom of the screen. That did it for me. Fan stopped running within minutes. Make sure there is no tape there, either… the vent should be clear.

  23. coldcomfort commented on Apr 13

    No solution, just sympathy. I have a G5 of the same vintage with the same problem. It has been in the shop on two occasions and taken over a week in each case to repair. This is in addition to one in-home repair. Logic board and power board have been replaced three times.

    Dust is a big problem so you might try buying a can of the compressed air, open the case and blow out the dust. I have searched the internet for some sort of external fan to increase airflow but have not been able to find anything.

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