Hi all. I have had problems with the fan on my 2012 iMac for the last week. The fan spins up to more than 4000 RPM, then goes back to 900-1000 RPM for a while, and then returns to above 4000 RPM again. This is happening despite the Mac idling. I have been monitoring the fan and temperatures for the last week, see the two screenshots below. The temperatures are stable around 26-45 Celsius and CPU is 90% idle. I tried resetting the SMC, but this did not change anything. What can I do to further troubleshoot? Any suggestions would be welcome.