fan is always running

The fan will run all the time, but if it is running at excessive speeds it can indicate a problem. Download, install and run iStat Pro to determine fan speeds and temperatures.

http://www.apple.com/downloads/dashboard/status/istatpro.html

Post back with results.

That's still not working stedman1: 27" iMac running a temperature!

Can you download it?

Which iMac...? see > How to identify iMac models

Reset the > System Management Controller (SMC)

1. Shut down the computer.

2. Unplug the computer's power cord.

3. Wait fifteen seconds.

4. Attach the computer's power cord.

5. Wait five seconds, then press the power button to turn on the computer.

Was the iMac just worked on..? Sometimes after a repair, one fan will run at full speed because someone did not properly reconnected a temp. sensor or installed an incompatible HDD.

I downloaded it less than a month ago. I will check on the iMac.

EDIT:

Well, that's peculiar. No longer available from teh Apple link. The MacUpdate site seems to be OK.

http://www.macupdate.com/app/mac/20364/istat-pro

Thanks for the heads up.

This one (free app) can be used to diagnose and fix fan issues on an Intel mac:

https://www.macupdate.com/app/mac/47386/macs-fan-control

I found an old fix from back in 2009 solved my problem, go to system pref,printer,open print queue, there I found o my mac was still trying to connect for an old print job 3 weeks ago, cancel job, Fantastic solved constant fan exess power and overheating.