Late 2009 iMac overheating

Discussion in 'iMac' started by misspaperwait, Sep 25, 2017.

  1. misspaperwait macrumors newbie

    Mar 6, 2011
    Okay so I know the system is older but it's in fantastic shape, I bought it from the original owner who barely even touched the thing (came with all the original packaging, manuals still in plastic and discs) years ago now and I myself have used it only very lightly.

    Shortly after I bought it I noticed if I used it for a long period of time that it would suddenly and without warning shut down. I later found out that the hard drive was dying and needed to be replaced.

    Fixed that problem and it's ran beautifully since up until yesterday that is.

    I've been working on data entry for work, I had safari open with google sheets running as well as a couple extra tabs of research stuff and youtube playing in the background.

    Yesterday it ran for a good 5-6 hours before it suddenly and without warning just shut off.

    I touching the upper left corner and realized it was super hot, figured I just had too much going on the poor old girl and I left it off for the night to cool down.

    Booted back up this afternoon to continue the work and again had youtube running in the back ground only today it got to work for maybe an hour, hour and half before it suddenly shut down again.

    Any suggestions to help cool the poor thing down so I can use it without it randomly shutting off on me?
  2. kschendel macrumors 65816

    Dec 9, 2014
    Take it apart again, blow out all dust, make sure the fan is running and not seized up.
  3. BrianBaughn macrumors 603


    Feb 13, 2011
    Baltimore, Maryland
  4. misspaperwait thread starter macrumors newbie

    Mar 6, 2011

    Nope, no glitches or any other anomalies at all actually. It goes from working perfectly to shut off, nothing happens before it goes off, like I was literally in the middle of typing a sentence and all of sudden it was off.
    --- Post Merged, Sep 26, 2017 ---
    As far as I can tell the fan is running, it runs very quietly
  5. redheeler macrumors 604


    Oct 17, 2014
    It's normal for the pre-2012 Intel iMacs to exhaust hot air and got hot on the top-left, that doesn't indicate anything wrong. Here are a couple things to try:
    • Run Apple Hardware Test.
    • Download SMCFanControl and monitor your system's temperature. If it turns out that your iMac is running abnormally hot, you can use SMCFanControl to increase the fan speed.
  6. misspaperwait thread starter macrumors newbie

    Mar 6, 2011

    I know it's normal for them to run hot, it's the fact that it's turning its self off that leads me to believe there's a problem, now whether that problem can be solved by simply increasing the fans I don't know lol thank you for the suggestion
  7. Colonel Panik macrumors regular

    Colonel Panik

    Feb 23, 2004
    Dublin, Ireland
    Maybe the heat sensor that you attached to the new HD has come loose, and it's shutting itself down after a while because it believes the temperature to be too high?
  8. guillepunx, Sep 27, 2017
    Last edited: Sep 27, 2017

    guillepunx macrumors newbie

    Sep 25, 2017
    I replaced my original ATI HD 4580 512mb GPU for an AMD 6970m 2gb GPU from an Alienware laptop, and the computer started to shut down it self when I was putting some games. So I bought some MX-4 thermal compound to replaced the first one that I puted and it fixed the problem.

    So maybe you should try to repaste your GPU, the true it's that the original paste on my ATI 4580 was really bad shape when I removed the videocard from the heatsink.

    update: I forgot to mention that I'm using Macs Fan Control, not Smcfancontrol, SSD Fan Control or HDD Fan Control.
    Macs Fan Control allow me to control de ODD (superdrive) fan with the GPU heatsink, so when that heatsink start to be hot, the fan speed up.

    Good luck :)
  9. misspaperwait thread starter macrumors newbie

    Mar 6, 2011

    How would I go about finding out if my thermal paste needs replacing? I can't say I've ever dealt with it before haha
  10. guillepunx macrumors newbie

    Sep 25, 2017
    It's normal that a computer that have been working for 8 years, the thermal paste on the CPU and on the GPU start to be in bad shape. Each two years for replace it should be ok. Of course it depends about how much you strees your GPU and CPU.

    Also there is crazy people saying on the internet that they replace the paste each 6 months... but that has no sense in my opinion.

    Other people said that the cooper pipes of the heatsinks may have leaks because they should have vapor inside for thermal transfer. But I'm not sure if it's true that this tiny cooper pipes have vapor inside.

    Hope this can help you :)
  11. kschendel macrumors 65816

    Dec 9, 2014
    I'm reasonably certain that there is no magic smoke inside the copper heatsink pipes.

    As for the thermal paste, you take the heat sink off and see what the thermal paste looks like. If it's dried up you replace it. If it wasn't dried up, you replace it anyway, because you have to do that once you disturb it.
  12. Ivanovitchk macrumors regular


    Sep 9, 2010
    Paris, FR
    heat pipes do contain a liquid (distilled water + anticorrosion mix usually)


    for the OP, as the others stated, clean (with isopropylic alcohol) both radiator base and cpu die / heatspreader and reapply paste correctly (not too much, not too little, seek guides if unsure).

    Good pastes like noctua / thermalright / artic silver... can be left for a few years before needing replacement.
  13. kschendel macrumors 65816

    Dec 9, 2014
    I wouldn't have thought that a CPU heat sink would have pipes long enough to gain any significant advantage from vapor transport, but I see that I am wrong; thanks for the correction. Whether the iMac uses that sort of cooler, I couldn't say.
  14. koden macrumors newbie

    Feb 13, 2016
    Hi.. I have a late 2009 imac. Yes it's hot on the top.
    But after replacing harddisk with SSD disk, I have no heating problems anymore.
    There is not hot on the top or any other place on the imac.... not at all...

    How can that be ?
    Is the standard harddisk making the heat?

    Further more it has become the most silence pc that I have ever had.
    No fan running (at least very slow) no HDD noise... maybe it use less power... so nice..
  15. zweirad macrumors newbie


    Jul 14, 2011
    north carolina
    This kind of a dumb question, but what has your experience been with the SSD? Did you do the transplant or hire someone to handle it?

    I'm also using a 2009 2.8GHz i7 iMac. I want a new one but have recently thought about modding this one to give it a little more life. If I replace the HDD with an SSD, will it give me another year of service? I put a new SSD in my laptop and it was like giving it a new lease on life: Adobe apps open quickly, no waiting for boot up, etc. The only other hangup with this iMac needing more RAM (16GB doesn't cut it anymore). Thanks!
  16. koden macrumors newbie

    Feb 13, 2016

    I just used

    a little expensive. But because I got a free SSD, I only had to pay for kit.

    I did it myself.
    There are "how to do" videos.

    The most important is to beware cables when you seperate the screen from the imac.
    Cable plugs can be sensitive. I did broke one of them :)

    I have 8 GB memory in mine and it's fine for what I use it for.
    I have no need for a new imac.

    My graphic card I have also fixed with the "baking" solution.

    Sorry for my english.... not my language :)
  17. EugW macrumors 603


    Jun 18, 2017
    How did you fix the cable? Did you have to buy a new one? If so, where did you get it?
  18. koden macrumors newbie

    Feb 13, 2016
    cable..? it was the cable connecting screen and imac inside imac.
    The big one... there are 4 cables.

    I found used on ebay.
  19. kschendel macrumors 65816

    Dec 9, 2014
    I did my own. Any 2.5 inch SATA SSD will work, and I used a little icy dock 2.5" to 3.5" adapter (not really necessary). I mostly followed the iFixit instructions, but read the comments first because you don't want to disconnect the display cable, just rotate the display out of the way. It's easy and takes maybe 45 minutes if you are working slowly and carefully.

    I did the SSD upgrade using a Mushkin 480GB in summer 2016 hoping to get another year out of the old iMac, and we're up to two and counting. I might replace the machine next summer -- or not!
  20. zweirad macrumors newbie


    Jul 14, 2011
    north carolina
    @kschendel Thanks for the follow-up. After watching the OWC and iFixIt videos, it looks pretty straightforward. The reviews on the OWC site are really positive for making the HDD to SSD upgrade.

    On another thread, someone mentioned that the SSD would only benefit the I/O performance of the drive/ They said that apps opened quickly but it didn't have much effect on the daily use of applications. I'm using this iMac for graphic design, mainly print and digital stuff but no video or audio. Do you think it's worth it to go for the upgrade?
  21. nambuccaheadsau macrumors 68000


    Oct 19, 2007
    Nambucca Heads Australia
    One word ~ for sure! Hey wait..that is two words but I am sure you get the message z.
  22. kschendel macrumors 65816

    Dec 9, 2014
    It's true that if the application sits there and does no storage I/O while you draw on the screen or whatever, that you won't see much difference during that time. The vast improvement in general interaction with the Finder, opening and saving files, picking through thumbnails, etc etc etc is entirely 100% worth it, IMO. Plus the application is probably saving undo records, there's background stuff going on that gets out of the way faster, and so on.

    I would never ever go back to a hard drive based system given anything remotely like a choice.
  23. arkieboy72472 macrumors member


    May 4, 2017
    My rule of thumb, and I may be in the minority, is if a machine is a 2012 or older, I remove all old paste and put on new. I think once every five years is good. It isn’t easy to disassemble and reassemble for a newbie but with the right tools you will be ok.

    A tear down also gives you the chance to blow it out good. Also a ssd won’t put off much heat if any and is an upgrade over a hdd

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22 September 25, 2017