It certainly is. I was lucky. I went to an authorized repair centre instead of Apple directly and after a few days of tests, the technician just decided to replace the whole board. Do you have an authorized repair centre near you? You may have better luck with them.
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Resolved 2020 27" iMac fan suddenly goes full throttle for a few minutes (about once a day)
- Thread starter RoboCop001
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It certainly is. I was lucky. I went to an authorized repair centre instead of Apple directly and after a few days of tests, the technician just decided to replace the whole board. Do you have an authorized repair centre near you? You may have better luck with them.
I started out going to Kangaroo Mobile, an authorized 3rd party place that mostly services iPhone & iPads, because there were no appointment times available at any of the Apple stores here whenever I tried to book one. But they could not determine why after two visits. It took a call to Apple Care to get me into a store, who had it for three days. They rain tests, wiped the hard drive, reinstalled the OS, and gave it back. It was quiet for a day or two before the fan began to fire up again. Out of desperation, I reinstalled MFC, even though it had previously stopped having any effect, and the fan has been quiet since then, 3 days ago. Can't count on this lasting, so I'm planning one more assault on the store, with video of the event... assuming it happens again soon... and stats from MFC, etc.
I have until Aug 23, when the 1 year refurb warranty runs out. Thanks for the encouragment.
Hopefully it doesn't come back for you. But if it does, yeah definitely insist. I feel like it's one of those things where they just can't figure out what's wrong.
In your case, does MFC report 0 RPMs as it's happening? That's what mine did, and I presume that if the sensor detects 0 RPMs, then the fan defaults to maximum speed.
I just figured it's some kind of hardware fault, maybe the fan sensor. When they replaced the logic board (including the fan, and everything) I had to restore from Time Machine. So in my case at least it's highly unlikely some lingering system glitch. My money is on some kind of hardware fault.
It might have during the previous 6 months, I'm not sure. Last time it did it, it did not. I took a screen shot of MFC then, which is attached. Pretty high number. And did I mention...? smacking the middle of the lower screen bezel, right on the Apple logo, usually made it stop.
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Actually now that you mention it, I do remember sometimes seeing an extremely high RPM like you as well.
Hahah if hitting it makes it stop, then there's definitely something wrong with some part that involves the fan. At first, my tech was going to replace just the fan. But he wanted to be totally sure so ended up doing the whole board. It took about a week for the parts to come in because I had a BTO.
Hello everyone. Faced this issue, too. Man it's so disturbing.
Now my Mac is in authorized service but specialists deny this issue, they say that "TESTS" show that everything is just fine. My mistake I didn't record the video of loud fan before. Any clues how can I convince the service center to make a replacement if they do not recognize a technical malfunction? It would be cool if there was some database of fixed issues in apple so I could link to it or smth.
So maybe I will have to replace the fan or motherboard by myself in non-authorized service.
My question is, can it be only fan that cause the issue?
RoboCop001 You replaced fan plus motherboard or motherboard only?
Whole motherboard replacement will be rather expensive and there are some problems with original apple parts shipment to Russian Federation due to political situation. I hope that it is enough to replace just the fan.
Sorry for my English btw, hope my message is understandable.
Now my Mac is in authorized service but specialists deny this issue, they say that "TESTS" show that everything is just fine. My mistake I didn't record the video of loud fan before. Any clues how can I convince the service center to make a replacement if they do not recognize a technical malfunction? It would be cool if there was some database of fixed issues in apple so I could link to it or smth.
So maybe I will have to replace the fan or motherboard by myself in non-authorized service.
My question is, can it be only fan that cause the issue?
RoboCop001 You replaced fan plus motherboard or motherboard only?
Whole motherboard replacement will be rather expensive and there are some problems with original apple parts shipment to Russian Federation due to political situation. I hope that it is enough to replace just the fan.
Sorry for my English btw, hope my message is understandable.
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I would just keep insisting and perhaps you can show them this thread as well.
Do you have Macs Fan Control installed? Or a similar program that can tell you the fan RPMs? I took a screenshot of the fan speed as it was happening, as well as normal fan speed, and sent this to the repair technician as proof. I would suggest doing this as well.
In my case, he decided to replace the entire board including the fan. He could not find the problem.
Is your machine still under warranty or Apple Care?
Yes, it shows nearly 4000 rpm same as Rickbot's fan. Same issue. Fool of me, I forgot to make screenshot but maybe Rickbot's photo will be useful.
No AC or reseller warranty, but we have Law on Consumer Protection here, so it gives 2 years warranty in certain circumstances. But it is necessary that problem will be admitted by service employee. Hope it will be.
Thank you for answer!
Oh! Also, while it's happening, take a screenshot of Activity Monitor. Both CPU and GPU usage. This is to show that the fan speed isn't related to heat or some background process that's taking up a lot of resources. I just remembered I also did this. While my fan was going, CPU/GPU usage was basically idle.
Something else to note is that the fan increases speed abruptly and not gradually. If it was a process or heat issue, the fan would speed up fairly gradually and not suddenly.
Hopefully this proves to your service centre that there is a problem, even though they can't find exactly what it is.
After a 3rd inconclusive repair attempt on fan over-speeding, this time at an Apple store, not 3rd party place, machine returned after analysis and testing with no repair made. They did wipe the hard drive in case that might've been an issue, but the Fan resumed over-speeding behavior with a few days. Out of desperation, I re-installed the Macs Fan Control app, which previously seems to have worked, but gradually became almost totally ineffective, and the fan has only surged occasionally. Not sure if MFS is the reason or not.
Spoke with AppleCare, and told them there's no point me hauling back in for repair again, unless they agree that if they can't nail the problem, they replace the motherboard, which seems to have been an effective solution described not only in this Mac Rumors thread, but other discussion groups. AppleCare not only agreed, but then added that they would otherwise replace the machine.
Music to my ears, and what I initially expected from Apple. This is a refurb 2020 27" iMac, under warranty until Aug 23, which covers either repairing the machine, or, if unfixable, a trade-in deal, (not at replacement,) on a similar refurb unit, which would only net me $750 for the old machine. (Which I paid almost $2600 for.) The return policy was only in effect for the first 2 weeks of ownership, and this issue didn't materialize for a month or two after purchase. No one mentioned "replacing" until that last AppleCare discussion. It took three repair attempts and numerous phone calls over several months to get this far.
I'll be taking it in this week, hopefully for the last time. Let's see if they deliver: repair, or replace.
Spoke with AppleCare, and told them there's no point me hauling back in for repair again, unless they agree that if they can't nail the problem, they replace the motherboard, which seems to have been an effective solution described not only in this Mac Rumors thread, but other discussion groups. AppleCare not only agreed, but then added that they would otherwise replace the machine.
Music to my ears, and what I initially expected from Apple. This is a refurb 2020 27" iMac, under warranty until Aug 23, which covers either repairing the machine, or, if unfixable, a trade-in deal, (not at replacement,) on a similar refurb unit, which would only net me $750 for the old machine. (Which I paid almost $2600 for.) The return policy was only in effect for the first 2 weeks of ownership, and this issue didn't materialize for a month or two after purchase. No one mentioned "replacing" until that last AppleCare discussion. It took three repair attempts and numerous phone calls over several months to get this far.
I'll be taking it in this week, hopefully for the last time. Let's see if they deliver: repair, or replace.
That’s good news! Though an annoyingly long time to get to that point. Hopefully you get this solved very soon. Good luck!
Couple days after I wrote in this thread that T2 chip restore probably helped, the fan start to spin high again. So i recorded a video of it and sent it back to the store where I bought the iMac. I have specifically asked for the repair technician to call me so I can send him the video of the problem and so far nobody has contacted me. It is now 9 days so I am wondering with what will they came back.
Definitely follow up with them. Mention as much info as you can and also take screenshots of the fan RPM status and also Activity Monitor CPU/GPU usage. And then just insist on a logic board replacement because that seems to be the only actual solution lol
The logic board replacement is infact what was suggested by the technician last time, so I am curious if they will replace it. For sure I will post here when I have something new
So good news!!! The authorized service provider decided to replace the logic board. They didn't even contacted me for the video of the fan throttling. TG PRO shows no fan issues so far, so I hope this is it then and no more fan issues from now on.
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Very interesting. I also have the same configuration (3.8Ghz i7 proc and Radeon 5700) since late August 2020. However I only noticed the fan spinning up when it's doing updates from the Mac App Store (notably Xcode) and having multiple browser windows (MS Edge, FireFox) opened.
That sounds normal to me. Lucky that you didn't have to deal with this! The most annoying part is the technicians have no idea what the problem is and in some cases will take a very long time to finally just replace the internals.
As long as you don’t hear them spinning high out of the ordinary I believe you should be OK. But you can always check for the temperature when the fan gets higher RPM. That is the easy part
Hello everyone.
Update for my situation.
Service center replaced the iMac case (shell) and logic board for free. So because nearly all parts are built in logic board, I also got new ssd, video card and CPU.
Problem with fan was solved.
BUT occurred another issue: in the beginning I brought iMac with 10-core i9 CPU for repair, but service gave me iMac with 8-core i7 CPU in return after logic board replacement.
It revealed that somehow reseller made funny business with my logic board initially and integrated i9 CPU non-officially to make it more expensive (?). According to the serial number and official specification, my board is listed as a board with i7 CPU, not i9. Service center could only order a completely matching spare part.
This situation is under apple support investigation right now.
Update for my situation.
Service center replaced the iMac case (shell) and logic board for free. So because nearly all parts are built in logic board, I also got new ssd, video card and CPU.
Problem with fan was solved.
BUT occurred another issue: in the beginning I brought iMac with 10-core i9 CPU for repair, but service gave me iMac with 8-core i7 CPU in return after logic board replacement.
It revealed that somehow reseller made funny business with my logic board initially and integrated i9 CPU non-officially to make it more expensive (?). According to the serial number and official specification, my board is listed as a board with i7 CPU, not i9. Service center could only order a completely matching spare part.
This situation is under apple support investigation right now.
Wow that's sneaky. Please update us when the investigation is done. Does that mean you paid more than you should have originally?
I hope you eventually get an i9 back, but in case that is refused or impossible: the i9 in the 2020 iMac is not greatly better than i7, and in many cases the i9 will throttle while the i7 does not.
More important is that your GPU does not also get downgraded.
Check this comparison, for example (although admittedly MaxTech do not tell the whole story):
I don’t think that’s the point here. Drama was charged more by reseller for buying the i9 and got i7 after the repair. Something is fishy here, but anyway you must have an invoice which proofs what you have been charged for. The law is on your side, so good luck and nerves.