Clicking noise - heard on back of iMac 27"

[Steve-ys7426]

Thanks for posting the video and sound sample. I have the same problem with my late 2013 27" iMac. I was upgrading to a SSD anyway, so I was hopeful the sound would go away. It did not--so apparently there was not a problem with a failing hard drive. The noise is intermittent, not present all the time. I have ordered a new fan and will see if that will solve this admittedly minor annoyance. I can't think of any other moving parts inside the machine that could be causing this "puttering" noise--can't think of any other way to describe it.

To All:

This is a follow-up to my previous comments. I have now replaced the fan on my 2013 iMac and the "clicking" nose has gone away. I will post again if the noise returns, but for now the problem seems to have been solved. Summary: When I replaced my original HD with a solid state drive the clicking remained. When the fan was replaced the noise stopped. There may be other causes of clicking noises like this, but for me--solution found.