[rjenkinson]

The hard drive in my Late 2009 27" iMac (11,1 )is failing, according to SMART status. The stock drive was a 1TB Seagate ST31000528ASQ. I'm planning to replace it with a 2TB Seagate Barracuda XT so I can attach the temperature monitor. Some people report problems with their fans, even after replacing the original drive with another from the same manufacturer.

Has anyone replaced the hard drive in a similar machine, or used this particular drive?

[rjenkinson]

Just as a follow up, the Barracuda XT seems to work fine with the iMac's temperature sensor, though I am using SMCfancontrol to raise the fan RPM and keep the drive at 40°C.

[CharlesS]

You should be able to find guides on iFixit. Expect it to be a PITA though. Apple really went out of their way to make the hard drive difficult to get at on the intel iMacs.

[P]

IMO, the 27"ers aren't that terribly to get to. It's daunting before you start, because you know you have to remove the entire display panel, but after that it's actually very easy to work with.

Note that the drive must be a 1/3 height (standard is 1/2 height) to fit in the drive.

[mkerr64]

should there be a need to replace and you wish to do it on your own this link may be helpful: iMac Intel 20" EMC 2266 Hard Drive Replacement - iFixit