iMac running very hot

There is NO other software than Safari running right now, while I was running iTues it was even hotter.

Just to test, quit Safari and wait a bit to see if the temps' come down. There have been some isolated cases of a misbehaving Safari causring overheating.

I wrote "iTues" earlier, I meant of course "iTunes"

That's OK I wrote "causring" but we know what we mean, or at least I do ! 😁

Back to your problem, it is good to get different approaches. I am glad you have someone from Apple helping you.

Can't hurt to try an SMC Reset. Pay attention to the timing in the instructions.

http://support.apple.com/kb/ht3964

Might also run the Hardware Test in Extended.

http://support.apple.com/kb/ht1509

Not all that good at picking up errors, but if it finds one it can be trusted.

Also, with the computer shut down or sleeping, vacuum the lower intake grille which runs along the bottom, where the speakers are located, and the one behind the stand; this is where dust accumulates. Heavy dust buildup might be a cause. Get iStat Pro. What are the fan speeds?

http://www.islayer.com/apps/istatpro/

Message was edited by: WZZZ

Your Ambient Air temp shows summer heat may be an issue here as they seem to be engineering their newer units to be running in climate controlled environments (68-72 F) With the intake air 20 degs warmer than they expect the system will naturally run hotter. More air movement can help (a small fan blowing on the rear of the unit)

In order for the SMC Reset to work the unit needs to be unplugged not just turned off. Then when the power is restored the time interval between the restoration of power and turning the unit on creates the reset. It is not just a matter of turning it on. Any self powered accessory needs to be disconnected.

If something, say the USB power, wasn't working and you do a SMC reset and it restores the power then you have a positive indication of a proper reset. Apple lists general, non specific, areas affected by the reset. I personally wish there were a LED indicator in the RAM bay to signal failure/success.

FWIW, those temps look very normal. Unless they start approaching 100°C, I'd quit worrying about it. Here are mine with a 7°F lower ambient air temp while running ML.

I use Carbon Copy Cloner to make bootable clones and 80 GB usually takes less than 40 min over FW 800 and faster when doing it internally from on volume to another. CCC also offers the ability to restore the Recovery HD. BTW, I don't use Time Machine.

Baltwo, FYI, the upper temp limit for most drives is 55C. Yours, at 58C, won't last very long like that. Even prolonged upper 40s, long term, isn't that healthy. And the OP's power supply was running very hot at 75C, not your relatively cool 58C.

Saying don't worry until the temps approach 100C is just plain insane.

Further reading on drive temps.

http://www.codinghorror.com/blog/2006/12/hard-drive-temperatures-be-afraid.html

Thanks for your concern. Then, I erred WRT to the int HD at 100°C. However, I just DL'd the Seagate manual and it shows:

Ambient temperature is defined as the temperature of the environment immediately surrounding the drive.

Actual drive case temperature should not exceed 69°C (156°F) within the operating ambient conditions.

Operating: 0° to 60°C (32° to 140°F)

Nonoperating: –40° to 70°C (–40° to 158°F)

When the original was replace under the iMac HD replacement program, the techs were satisfied that the temp was OK. Still have 11°C to go, since the temp sensor is on the drive case.😉