Just did it!

After 30+ years with PCs, I was given a non-working iMac. Decided the hd was at fault and replaced it following the instruction online. It's now up and running. Hooray! I've noticed that my iMac, (early 2009 24") runs really hot. Checking the sensors I find that the power supply is running at 176 degrees F. Logic board at 126F and the Northbridge chip and heat sink are at 165 & 156F. Just wondering whether this is considered normal. Any thoughts on the subject will be appreciated. Thanks for looking.

To me…those temps would be ok if you were using a Apple laptop…but they do seem a bit high on an iMac. Of course if you are gaming, watching a lot of internet video, or some video rendering…this could at least partially explain higher temps.

But if you are not doing anything special (just e-mail, internet webpage browsing)…then these temps seem high for an iMac.

I think that I would verify that all of the fans are operational…and give the inside a good cleaning (compressed air).

- Nick

p.s. The logic board temp is probably ok…it's the other temps that seem high.

Have a bit of a read through of this thread (http://www.mac-forums.com/forums/apple-notebooks/194862-official-my-macbook-air-pro-overheating-what-do-i-do-guide.html). Even though it pertains mainly to Apple Notebooks, there is still a lot of good information in there for everyone.

robpopper said:

After 30+ years with PCs, I was given a non-working iMac. Decided the hd was at fault and replaced it following the instruction online. It's now up and running. Hooray! I've noticed that my iMac, (early 2009 24") runs really hot. Checking the sensors I find that the power supply is running at 176 degrees F. Logic board at 126F and the Northbridge chip and heat sink are at 165 & 156F. Just wondering whether this is considered normal. Any thoughts on the subject will be appreciated. Thanks for looking.

Click to expand...

Those temps do seem a bit high for an iMac. Your iMac should have three fans: CPU, Hard Drive, and Optical Drive. Make sure all three fans are running and that they ramp up (higher rpm) when the temps rise.

Clean the intake vents at the bottom of the display and also the exhaust vents at the top - making sure they're not plugged with dust, dirt, animal hair, etc.

Thanks all for the speedy replies. Having just replaced the hd, I'm not all that anxious to go inside again.But will do so if expert opinion thinks it's necessary. (Although I don't want to see caps explode or worse.) Would you consider the temps listed as "dangerously high". Just normal internet browsing, not gaming or retouching images when temp were shown.

Congratulations on your "switch" and your iMac restoration fix.

Those temps are within max limits but are a bit on the high side for my liking, especially if there's no heavy use.

I found I needed to use an appropriate "fan control" for those and earlier aluminum iMacs (the white plastic caseiMacs were even worse) and I gather that all sensors were reattached correctly.

Maybe check out:
Diagnosing 2009 & 2010 iMac Fan Speed Issues After Upgrading The Main Hard Drive | Other World Computing Blog

100% sure about the model? Both the early and late 2009 model ahd 2.66GHz but on some late 2009 models, Apple introduced a hard drive with special heat sensors which can cause problems as set out in the above link. Also check out step 13 on this link on these heat sensors.


https://www.ifixit.com/Guide/iMac+Intel+24-Inch+EMC+2267+Hard+Drive+Replacement/9028#s4929

Many thanks for the information and the terrific support. I did replace the hd with a Toshiba 2T drive and I replaced the sensor correctly. Now going to check the link above and will post back shortly. Thx all.

What app are you using to get those temps? I would use C instead of F BTW as most like me know temps in Centigrade better.

Wow!!! For someone from Modesto, Ca I'm most impressed that you and "most like"you actually mostly use Centigrade. Not so for the average American, nor like most in the HVAC and similar industries where Fahrenheit is still the standard - even in Canada.

Fahrenheit Versus Celsius: Why the US Hasn't Converted - Weather Glossary - AccuWeather.com

But maybe that's why Apple provides a handy Calculator with a converter. ;-)

Actually almost every program I have ever used on PC's and Macs for he last 15-20 years defaulted to Centigrade. Most Temp readings are quoted that way also. I am not used to see F used for computer temps and I have been around on all the large support forums for many years and a long time computer tech! Grin

Otherwise I would agree with you on C Vs F. I have had many joking wars here on the forums about the two with our Canadian members!

Now using iStat/Menu and the numbers reported are somewhat lower. I'm accepting them as normal. I totally respect those with a greater knowledge as I've just switched,(and loving it!) but as for temperature readouts I'm going to stay with the big "F". Btw, I've just added a powered usb hub as I will be using 3- printers, Wacom tablet, external hd, external optical drive, BT keyboard and mouse; though not all at the same time...

As always, I appreciate all the kind help at this forum. Thx loads.

Winter Down under and my iMac reads:-

Ambient 9º, HD and CPU 19º and Power Supplyº, all of course in ºC.

Wouldn't mind things being warmer all round!

Days here lately have been sunny with white puffy clouds. Temps in the upper 70s and lower 80s, all of course in degrees F. My aluminum iMac is running like a Swiss watch.