CPU fan running full speed after 15 minutes

My 3 month old iMac 24" has just started having fan problems.
Before I went away on a training course, it was working fine. Left it switched off at the outlet for 3 days, now the CPU fan runs full speed after the iMac has been switched on for 15 to 20 minutes.
CPU temp is 24C, CPU heatsink is 28C. Ambient is 17C. CPU fan is 3600rpm. Other fans are normal.
CPU usage is less that 10%. Only Safari is running.
I've tried resetting the SMC - left all plugs disconnected for 15 minutes, reconnected mains power for 15 minutes, reconnected USB, then switched on.
Still the same - OK for 15 minutes, then CPU fan runs full speed.
Anything else that I can try?

I tried again, following your instructions exactly. It seemed to work, running normally for about an hour.
I left all the USB devices unplugged, except for the keyboard and mouse.
I then shut the iMac down, but left the mains power turned on at the wall. When I switched it on again 2 hours later, all was OK for 15 minutes, then the CPU fan ran at full speed.
Shutting down for a few seconds fixes it for another 15 minutes.
I'm wondering if it's a software problem, although I haven't loaded any apps recently, apart from a few monitoring programs since this problem appeared.
Last night I left it running the extended hardware test for a couple of hours, and the fans were fine.
One thing that I noticed yesterday was that the "GPU" temperature readings in iStat were all missing (just "-" displayed) for a couple of seconds when I clicked on Dashboard. Is there a way to keep iStat open while I'm using the iMac?
I think I'll try booting XP and see what happens.

Similar Messages

Fans running full speed after hard drive replacement

I have a 24" aluminum iMac (iMac7,1) which had a hard drive failure. I replaced the hard drive myself and all went well. However, now my fans are running full speed. This appears to be because of a problem with detecting my temperature sensors now. During the install I only touched two temp. sensors, the hard drive sensor and the LCD sensor. I made special care to make sure I got the sensors back in place.
Using iStat Pro the only temp. sensors I have readings for are the Hard Drive and Power Supply. I am missing ambient, optical drive, CPU, and display. Out of those the only one out of the missing ones I touched are the display one. I have since gone back into the machine to ensure the LCD temp. sensor was fully connected and to ensure the HD one was connected (although that one is working).
What is really strange is the ambient sensor appears to be a diode on the main board so I really don't see a way I could have messed that one up. Also, I didn't touch the CPU sensor (didn't even see it), nor did I touch the optical sensor.
Anyway I have tried:
PRAM reset
SMC reset
went back into the box to make sure all temp sensors where in place.
I am out of troubleshooting ideas. Can anyone provide additional insight?

Mechanic man thanks for the response.
Besides for the fan noise the machine is running like a champ. The new hard drive seems to be fine, actually my machine boots up faster now than it ever did (faster drive I suppose). I ran disk utility and did a verify on the new disk and it didn't detect any problems.
The fans run at full speed immediately at power-on (maybe a one second pause). I first noticed it when I booted up from the startup disk to do a time machine restore. So yes, it occurs when booting from a system disk.
I have been unable to run Apple Hardware Test, I saw this step in some google searching and Apple docs but I don't seem to have AHT on any disk. I have tried putting the Snow Leopard disk in and holding "d" at boot time to no affect. I did some further reading and found that AHT may only be included on disks that come with the machine. I am going to try to dig up my Tiger disks and see if I can get AHT to run from there (10.4 was the factory installed OS when I bought my iMac).
I am also considering trying to re-install SMC firmware (http://support.apple.com/kb/HT2368). Even though it will be the same version at least I know the SMC reset has taken place.
Since the fans run full speed right at start up that suggests to me that it is a physical hardware problem (i.e. something wrong with the sensors) or a firmware issue. I am leaning toward firmware.

Mac Pro fans run full speed after installing Solid State Drives

I recently visited the Genius Bar at my local Apple store because my Mac Pro's fans were running at full speed after installing 2 solid state drives. The genius told me that it was because the drives themselves are so small they don't touch the metal tab on the motherboard that reads the drive's temperature, so it defaults to running full speed. Does anyone know how to fix this problem? I've tried smcFan Control but it doesn't let me set the actual fan speed. I'm getting 5200 rpms on my Boost A and B fans, and this causes an insane amount of noise. Can anyone help?

Which model Mac Pro?
I have an SSD in a 2009 (MacPro4,1). I removed it from the 2.5 in stamped metal can, and just installed the bare circuit board onto the SATA connector. It does not make any contact with the metal tab below the SATA connector. The only trouble I have is that Tech Tool Pro says its temperature is not optimum when it does disk tests.

Fans Run Full Speed After Upgrades

I have a late 2007 15" Macbook Pro. I just recently replaced the hard drive (because i needed more space) and the keyboard (because it was defective) and since i've put it back together the fans are always running at full speed. I do have an smc control app but the adjustments i make are not affecting the fan speed at all. Does anyone know what I might have done wrong to cause this? and is it something I can fix?

I've checked all the connections and I don't appear to see anything loose, or any crimped or cut wires. Someone though it might be that the new hard drive I put in runs at a higher rpm (7200) than the original 5400rpm drive, but that was ruled out after placing the original drive back in. At this point it looks like I may be replacing this laptop if I can't get this issue resolved.

Fan runs full speed at start up

HP Pavilion p6-2037cb purchased 1/19/12. Windows 7. There is no error message.
When I turn the computer on after it has been off all night the fan runs full speed. This happened a few times in the first month. The first time it stopped itself after a few minutes. Then I learned to stop it by simply restarting the computer. This still works, but what used to happen a couple times a month, has happened twice in two days so I worry the problem is getting worse.
It never happens when I am using the computer because I do nothing that requires a lot of cpu's or causes heating. I just surf the web and do email. No games or videos or TV.
If it is a fan connection problem I would like to know the nearest repair service. I would rather bring it in than ship it. But I can't find a list of authorized warranty repair service centers. I followed links on HP Support Assistant but got sent to a site that does not list Pavilions.
I need to know why the fan runs full speed at start up and where to get it fixed near where I live.
This question was solved.
View Solution.

Hello mpw101,
Seems like there was some confusion on the products your received and how it was explained. I have forwarded your thread to the appropriate team for review. Someone should be in contact with you shortly so you can discuss your HP customer care experience.
If I have helped you in any way click the Kudos button to say Thanks.
The community works together, click Accept as Solution on the post that solves your issue for other members of the community to benefit from the solution.
- Friendship is magical.

Classic makes fans run full speed

I think this is new. When I run Classic my fans run full speed (10.4.8 G5 iMac 20") with any of the kid's games. I've done the SMU reset, blown dust from vents, tried different power settings. I think blowing out the dust reduced fan use in OS X, but not in classic.
Thermograph data suggests the fans are behaving appropriately, so I think the system is running hotter than in the past. Anyone have other ideas? Anyone else seeing this classic behavior?

Have a look at one post I made some months ago :
http://discussions.apple.com/message.jspa?messageID=1621311#1621311
I discovered that going back to Classic from one user to the other make a large use of CPU (80 to 90%) thus rising the temperature and conversly the fan...
If you open classic in one enironnment that's not true. Check it with Acivity Monitor.
Hope this helps.
JfS

Fans run full speed when using Parallels

I have Parallels installed on my MacBook but the problems is, whenever I run Windows XP, the fans run at full speed. I try not to run too many programs but nothing seems to help.
Any suggestions?

I think that it's normal that the fans run full speed when you use Parallels. It also means that your MacBook's thermal paste was applied well.
Runing Windows XP in Parallels is a CPU intensive task and it takes a lot of power to run it. As a consequence the CPU get hot and the heat is transfered to the cooler, where the temp sensors sense it and make the fans run faster.
It's normal.
I bet your MB doesn't get as hot as some do...

Spinning beach ball of death after crash with fans running full speed

I recently put my machine to sleep - came in the next morning to find it running all fans at full speed and frozen. Did a hard reset (power button in for 5 seconds waited 15 secs and then power on. It rebooted after a long re-boot period. Since then it has slowed down. Many apps take an age to open. Many freeze and there is the infamous SBoD. I have rebuilt permissions, installed 10.5.8 combo, done a permission repair from a separate firewire disk, run onyx - which at time never ends and has to be aborted. Activity monitor shows no exceptional activity when the SBoD is running. I had significant issues until last December when i did a clean rebuild and installation of leopard and put all essential software in from clean install disks - all in all had a pristine machine which was working perfectly until the week before last when the full fan and freeze crash occurred. I notice that it speeded up after the 10.5.8 combo install and permission rebuild from external disk but gradually slows down and gets increasingly unstable requiring forced reboots more and more often. I have no hacks or other background processes other than Virus Barrier 6 which ran perfectly before the crash.

As expected after running well at about 11:40 Mail slowed down and the SBoD started.
The console shows the following:
19/2/10 11:40:00 AM [0x0-0x6d06d].org.mozilla.firefox[4570] Debugger() was called!
19/2/10 11:42:42 AM [0x0-0x6f06f].com.apple.Safari[4671] Debugger() was called!
19/2/10 11:55:22 AM Automator Runner[5082] Error while processing arguments
19/2/10 11:56:47 AM Automator Runner[5130] Error while processing arguments
19/2/10 12:06:08 PM Automator Runner[5420] Error while processing arguments
19/2/10 12:06:54 PM com.apple.launchd[378] (com.apple.Safari[5451]) Check-in of Mach service failed. PID 5451 is not privileged: com.apple.Safari.SyncClient.IsRunning
19/2/10 12:06:54 PM com.apple.launchd[378] (com.apple.Safari[5451]) Exited with exit code: 1
19/2/10 12:07:22 PM Mail[5429] Expected Apple Mail To Do to be selected for Operation "UID STORE", EXECUTING <0x179e47e0>
Dependency: Operation "DONE", DONE <0x17f1c1e0>
Dependency: Operation "IDLE", DONE <0x1843e0b0>
Dependency: Operation "SELECT", DONE <0x17f22ee0>
Mailbox name: Apple Mail To Do
Mailbox name: Apple Mail To Do, had IMAPMailbox INBOX:
EXISTS:32, UIDNEXT:5553, UIDVALIDITY:1226484816 instead
19/2/10 12:12:41 PM Quicksilver[425] * -[NSCFString string]: unrecognized selector sent to instance 0xd4abe0
19/2/10 12:12:41 PM Quicksilver[425] HIToolbox: ignoring exception '* -[NSCFString string]: unrecognized selector sent to instance 0xd4abe0' that raised inside Carbon event dispatch
19/2/10 12:12:41 PM Quicksilver[425] HIToolbox: ignoring exception '* -[NSCFString string]: unrecognized selector sent to instance 0xd4abe0' that raised inside Carbon event dispatch

K8N Neo-FSR CPU fan at full throttle after wake up from S3 (Suspend to RAM)

Hi,
using either Core Center or BIOS' smart cpu fan control my cpu fan throttles down to less than 2000 RPM without system load. Fine! But after wake up from S3 (Suspend to RAM) power down the cpu fan runs forever at full throttle with about >5000 RPM, making lots of noise. So far I didn't succeed neither with BIOS settings nor using Core Center to gain fan control after S3 wake up. Since Core Center apparently shows up the cpu temperature correctly with less than 40 degrees Celsius this may be a BIOS 1.4 bug.
Can someone please point me into the right direction? Yep, I did read the FAQ and already use board's search function :-)
Falo

addendum
did some further testing. Apparently this doesn't happen if I wait at least a couple of minutes between shutdown to S3 and wake up. In this case fan control works as expected afterwards.
Falo

IMac fans running full speed constantly.

A few days ago my iMac's fans started running at full speed, which they very rarely do. Now every time I turn on my computer after about a minute the fans reach full speed, I'm only opening Google Chrome, Twitter, iTunes and Coversutra which has never caused the fans to run before.
I've downloaded a program to monitor temperatures of various parts of the iMac but nothing is getting hot enough to cause the fans to run at full speed.
I have reset the SMC and PRAM multiple times which hasn't fixed the issue. I've run the Apple Hardware Test on the original install disks which gave an issue number relating to the fact that the fans are running on full speed.. surprise surprise...
The computer isn't very old, was purchased almost to this date in 2009. It's an 8,1 iMac with a 20" screen. 4GB RAM and a 2.4Ghz processor.
Would be extremely appreciative if anyone has any idea how to fix this problem.

Get free iStat Pro. This code is obviously related to the HD, but I don't know if it necessarily means the HD is failing. It will show the fan rpms to see which fan is revving up. If it's only the HD fan that is climbing up, this may be related to the HD temperature sensor being faulty. Thing is, the sensor is probably integrated into the drive, so if it's only that that's failing, it will still involve replacing the drive.
http://www.islayer.com/apps/istatpro/
Also, run the demo of SMART utility to check out your drive.
http://www.volitans-software.com/smart_utility.php
What does it say for SMART Status for the drive in Disk Utility?

Cold MBP, exhaust fan running full speed

Hello,
My 3mo old MBP exhaust fan has started running full speed (6200rpm), no processes or heat are to blame.
iStat pro say's the fan is currently at 6196rpm, highest temp sensor is at 30 degrees C.
Process monitoring says kernel_task using 160% of my two cores (interrupts?), this is a cause or a effect.
Reseting SMC had no improvement (unsure if I've managed to do correctly). Appart from that the machine works, very slowly, noisy, and very cold on my laps.
I'm on a business trip, don't have the diagnostic CD with me...
Any ideas so I can at least work during this trip ?
Thanks for your help, and for these forums.

Hello folks,
I'm in the same situation, the only difference is my hardware from 2006:
Model Name: MacBook Pro
Model Identifier: MacBookPro1,2
Processor Name: Intel Core Duo
Processor Speed: 2,16 GHz
After running the ASD, I got this:
+Temp Sensor - Palm rest L test 1 - Sensor Reads Within Operating Range.+
+-Check to ensure that sensor reads within operating range.+
+ERROR - Unable to read sensor+
+- T E S T F A I L E D -+
The sensor code is the same one from the post above: Ts0P.
So now, after looking for more than 4 hours on the internet, I couldn't find a clue.
What exactly is the location of this sensor?
Can someone please post a picture?
How can i fix this?
Thanks for everybody.
Message was edited by: Pierobon
Message was edited by: Pierobon

IMac CPU fan on full speed from start up

Hi,
For about 3 months now I've had a problem with my iMac where the CPU fan runs at full speed from start up, until I turn it off. It is extremley noisy and frustating.
I am pulling my hair out trying to fix it.
So far I have reset the SMC and PRAM and downloaded fan controllers. I've also opened it up and checked the sensors and cleaned out all of the dust, but this annoying problem still persists.
Is there anything else I could try that could fix this problem?
Thank you very much.

Thank you
I have tried to run the AHT many times, but for some reason I can't get it to work. I even tried booting it from the insitallation disk which someone else suggested.
I'm not sure where to go from here

Power Mac G5 apple logo stuck and fans running full speed

HI everybody,
I have been looking around in many forums and i noticed that a lot of people encountered a similar problem. Unfortunately untill now, nobody could give a real suggestion on how solve this issue.
In few words, my G5 (late 2005) 2gh 5gb ram 10.5.8 get stuck to the apple logo (grey initial screen) without going trough the start up. After a while the fans start to run full speed.
I have tried several solutions....but nothing so for.
I have reset the SMU button.
I removed all the ram slot and changed position.
The HD is ok and empty.
I even tried to warm the logic board with an hair drier as i read in a discussion...and i don't know why, the G5 could go trough the start up. Since it was active, i run the apple test. Result: All Ok
After rebooting successfully for 4/5 times, i switched it off. The morning after the G5 was dead again.
I am kind of lost.
Any suggestion?
Tnx

Try a Heat gun...
https://discussions.apple.com/message/16781690#16781690

Mac mini server and harddrive 1 of 2 failed now fan runs full speed

I have a 2010 mac mini server. One of the drives failed.
I took out the bad one and the fan started to run full speed.
Replaced that drive with a new one. runs great but fan is running.
I put the temp sensor in exact same place but had to use a small pc of tape
to hold it on. I used the same tape that was holding the wires to the drive.
I used the temp sensor connector on the logic board closest to the fan connector?
Does that matter?

Hello, possible work arounds...
HDD Fan Control
HDD Fan Control works to fix this issue by reading the drives internal temperature using the S.M.A.R.T protocol and set the fans actual speed to a value good to protect the drive.  It runs at startup and continually to always control the fan correctly, prevent the loud fan noise and protect the drive from overheating.
Free SSDFan Control...
http://exirion.net/ssdfanctrl/

Tecra A10-S3501 Power Light Flashes, Fan Runs Full Speed.

Greets all,
I have a customers Tecra in the shop, and after getting a good description of what was happening at the tme of failure, I still cannot seem to figure it out. She was watching a flash video when it froze. Upon reboot, it will not init the LCD, it does seem to at least partially POST, cd drive spins up, and all LCDs blink like normal. Still no LCD init, and the power light blinks green, no pattern, it is not a binary post led code. Fan spins up directly to full speed and stays there for the duration. I counted 20 one second blinks with fan at full speed, before powering down. Any ideas? Customer has no warranty, so would be nice to fix it for her. :-) Thank you, and have a great day.
Y

Hey,
Can you see a picture on external monitor? If yes it might be only a FL inverter issue of internal display. This is not an expensive part so this would be easy to fix the problem.
Anyway, if you cant see a picture on external monitor, I think its related to another part, maybe mainboard or something else. This should be checked from an authorized service provider
By the way: If you have connected an external monitor, use FN+F5 key combination to switch between them

CPU fan running full speed after 15 minutes

Similar Messages

Maybe you are looking for