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Level 1

5 points

21.5' iMac fan speed is to fast

Hi all,

I've got a problem with my new 21.5' iMac. According to iStat the hard drive fan is spinning way to fast. Now this has been happening at least once every 8-9 days since I got this machine about 4 weeks ago. I've been searching this forum and the net to find a solution and there doesn't seem to be any. When I called Apple last week the CSR told me that when I'm not using the comp I should shut it down. I'm sorry but that's not the solution. Has anyone heard if Apple is going to fix this issue?

Wow! As I'm typing this the fan is now increasing in fan speed. Under iStat it's saying that it's the hard drive fan that's the issue. It went from 1099rpm and it's continuing to climb in speed. It's now over 4800rpm and still climbing. In the past I've never been at the comp when it's started doing it. I did take it to a local Apple authorized repair shop and form 2 days they ran some tests and couldn't get the comps fan to reproduce the issue. The tech said he called Apple and they are not even saying there is a problem. he seems to think that at some point Apple will send a firmware update down to fix the issue. Now I've had my comp back from the repair shop for 8 days now and low and behold I had the fan problem right on schedule. What should I do? Should I call Apple again?

Thanks so much,
Chevy

21.5' Imac, Mac OS X (10.6.2)

Posted on Mar 20, 2010 10:46 AM

527 replies

Apr 21, 2010 8:35 PM in response to pauvregaspard

I have had the sleep mode turned on for both the computer and the display and have the fan problem. The delay is set for 10 minutes. Someone else mentioned that it didn't occur for the first three weeks. I wasn't keeping track of time the first time it happened, but I had owned the machine for a few weeks before it happened the first time.

Apr 26, 2010 11:11 AM in response to chevy2410

Hi all,

The last I wrote was 7 days since my last fan noise problem so it was ready to blow. That day I saw discussion on sleep mode. I always use sleep mode after 15 min idle time. Well, I went into preferences; energy saver; schedule..... I set it to go to sleep at midnight on that Thursday night (April 22). My last fan problem was April 15th. I have had no problem since that day. Most strange. I assume everyone is still having the same problem??? Don't really know how that would affect it but might be worth a try to see if it stops for others. I'll keep you posted as to future noise as it has been 11 days now and that is totally unusual. I did NOT do a shut down during those 11 days. My Mac runs 24/7.

Hershey's Mom

chevy2410 Author

Level 1

5 points

Apr 26, 2010 2:10 PM in response to Hersheys Mom

Hey Hersheys Mom,

So did you put the whole computer to sleep? I have mine run 24/7 and have only the monitor turn off after 15 minutes of no use. I heard from the Apple Authorize repair depot that I originally took my iMac to get it looked at and tested and they are telling me that Apple has said to them to replace the fan and the sensor cable for the hard drive. Now I'm pretty sure it's not the fan and it could very well be the cable, but if it is the cable you would figure that it would then report the incorrect temp readings. Well I guess you kind of need to start somewhere and then see what happens.

I just got off with the senior tech advisor at Apple and told him what the repair depot said to me and he wants me to get both the cable and fan replaced. The engineers all so looked at the file I sent them and they believe it has to do with a sensor. Well I say whatever! I'm getting the fan and cable replaced and if still does it then I think a new machine is in order. We'll see.

Chevy.

Apr 28, 2010 8:33 PM in response to chevy2410

Chevy,

I am now at 13 days since my last fan noise. This is awesome. In answer to your question, duh, I'm not sure. I have my computer on 24/7 but I allow the display and computer to sleep after 15 minutes idle time. To get this last part, I went into the schedule area and scheduled it to sleep at midnight Thursday. I don't actually know if that is the whole computer sleeping or not. Sorry I can't answer that one. But. . . I am ecstatic that the fan noise has stopped for now. Tomorrow will be 2 whole weeks.

Am anxious to hear if your problem stops with the sensor, etc. Have heard nothing new from anyone else. Does that mean all have stopped the noisy fans?? Maybe it was only a problem that lasted for 2 to 3 months??

Hershey's Mom

jsf4

Level 1

0 points

Apr 29, 2010 5:18 AM in response to chevy2410

Hello Everyone,

I have been reading your progress but waited until my
machine was ready to have the fan go on.
I decided to let it happen and monitor Activity Monitor and
the Console messages to see what I could learn.
Well, it did not happen this morning as I expected it to.

I did one thing in the meantime.

The reason I stopped sleeping my computer was to allow a weather station
program to run all night. It was not working as I wanted and I noticed it generated
lots and lots of messages to the console. That was very troubling
so I removed it the other day.

And now, the fan did not go on as expected.

So, I will see how it works going forward.

Seems like too many variables to come to a firm conclusion
on this issue but I would urge everyone to keep
reporting so we can see how it goes.

Glad Chevy and Hershey's Mom are making progress.

Jerry

chevy2410 Author

Level 1

5 points

Apr 29, 2010 1:18 PM in response to jsf4

Well got my iMac back and so far the only difference is that the HD temp now reads 1 degree Celius cooler than before. Not sure if that will make a difference or not, but knows. I had the HD sensor cable and HD fan replaced. I won't know until next Wednesday May 5 2010 to see if the fan will go nuts. I'll report back and let you all know either way.

Cheers,
Chevy

Apr 29, 2010 3:08 PM in response to chevy2410

Finally called my issue into Apple and talked to a Senior Advisor after having a Sr. Engineer here yesterday.

Opened a case w/Apple and performed another SMC reset on the machines and sent off a system report to them as well. Was advised to wait 7-8 days like usual to see if issue returns.

Note: The machines (46 of them) are all stock running no CPU intensive tasks, Anti-Virus/Malware/Spyware apps, etc.

Apple's initial concern was that there was something running in the background causing the HD to get too hot, which would cause the HD fan to go nuts. Sounds plausible, however, simply turning the machine off and on resolves the fan issue. If the HD was too hot, the fans would go nuts again after a power cycle.

Was also advised that the SMC reset process I initially did was "wrong" however I followed EXACTLY what is written @ http://support.apple.com/kb/HT3964?viewlocale=en_US. The procedure I was advised to follow was unplugging EVERYTHING, wait at least 30 seconds, then plug everything in and boot up. We'll see if this works, and if so, I will make sure to advise them that their support/KB article is incorrect or needs to be updated with this other procedure.

...more to come in about 8 days.

Apr 29, 2010 9:09 PM in response to chevy2410

Hi guys,

Well, doggone, my fan just went bonkers tonight. I really had hoped it was over for me. I shut down and started back up and it, of course, stopped. It had been 14 days.

Sure hope we get some good news soon.
Hershey's Mom

jmgbomb

Level 1

0 points

Apr 30, 2010 2:08 AM in response to chevy2410

I am having the exact same problem with my 27' i7 iMac. The hard drive fan is running between 4,000 - 5,000 rpms. I put the computer to sleep. Wait a couple of minutes, and when I wake it up, the fan has slowed to about 950 rpms. It then slowly but surely (like over the course of a few minutes) winds itself back up to over 4,000 rpms. And it is NOISY!! Part of why I sold my old Power Mac G5 was because of how noisy the fans got when any processing was happening. I did NOT expect this from a brand new iMac. Please look at all these posts Apple and resolve the issue.

drvans

Level 1

0 points

Apr 30, 2010 4:46 AM in response to jmgbomb

I have the same issue. Every week or so, always when I come down to the main floor computer room in the morning. Sounds like an engine running! At this point I have only done the shut down routine to get rid of it, but I'll call Apple sometime this weekend. I'm not sure if I should leave it run until then...will leaving the fan run like this for a couple days harm anything?

jsf4

Level 1

0 points

Apr 30, 2010 6:08 AM in response to chevy2410

Hi Everyone,

Oh no! I thought Hershey's Mom was over the problem but
I guess not. What were the circumstances?? Was the computer sleeping
or just running normally?

I noticed in Jason's response that the Apple guy thought
perhaps something was running in the background causing
the HD to heat up and the sensor to start the fan.

I have a theory that there could be some stuff running that
causes writes to the HD and then some Apple software that
sees this happening and concludes the HD could be overheating
and starts the fan.

As I said earlier, I found some software I was using was
causing hundreds of console messages. When I stopped that,
the fan did not go on as scheduled on Thursday.

It would be useful if some of you looked at
the Console messages (Console program in Utilities)
to see if something funny is happening.

I guess we must continue to gather data
and see if we get some good news from someone.

Jerry

Apr 30, 2010 1:20 PM in response to Hersheys Mom

Hersheys Mom

During the 14-day test (with sleep scheduled for midnight), at what time the next day did you typically use the system for the first time?

I'm guessing 10 a.m. (on average, over the 14 days).

Chris Beall

May 1, 2010 12:32 PM in response to Chris Beall

Chris,

Misconception on the sleep mode for my computer. I put it to sleep ONLY one day a week, Wednesday at midnight. I can see where your thinking was going maybe but it wasn't in sleep mode every night. Sorry.

Let's hope Chevy has some good results. I think we are all waiting and hoping for that so we know how to proceed.

Hershey's Mom

May 1, 2010 2:07 PM in response to Hersheys Mom

OK, thanks. So putting the system to sleep for, let's say, 8 hours or so, extended the time-to-failure from 8 days to 14.

Back to the drawing board...

Chris Beall

jsf4

Level 1

0 points

May 1, 2010 2:59 PM in response to chevy2410

Hello Chris ,Hershey's Mom and Everyone,

It was interesting to note that Hershey's Mom's computer was not asleep when
the fan went on again.

I still believe there is some software running periodically
that thinks something is wrong and turns the fan on.

I found a program creating hundreds (maybe thousands)
of error messages to the console and turned it off.
The fan did not go on as I had expected and I did not
have the computer asleep.

I now need to wait until next week to see if the fan still stays off.

My theory is that sleeping the computer prevents either the periodic
software from running or the problematic software from
running or both.

Anyway, we should continue to keep each other informed
as to what is going on.

I still think it would be helpful
if some of you looked at
the Console (in Utilities) to see if you see a large number of
messages or something weird.

Thanks for your help.

Jerry

21.5' iMac fan speed is to fast