Fan acting crasy af SSD upgrade

Hello out there,

I’ve recently upgraded my iMac Intel 21.5” Late 2013 with a Samsung EVO 860 500GB SSD instead of the original HDD.

I’ve followed the instructions on ifixit and multiple YouTube-videos and didn’t have any problems in the process.

Afterwards i’ve got a lot of problems with the fan acting crazy even when I only perform simple tasks.

It happens especially after the iMac has been shot down or waken from sleep. Sometimes the fan is at full blast of over 4000 rpm, and other times it switch between 0 rpm for a couple of seconds and 4000 rpm for a couple of seconds and so on.

Have I done something wrong? Should i’ve installed a Thermal Sensor on the drive? Many places people stated that it could fix the problem, but as far as I can see, it’s only necessary on iMac 27” or older 21.5”.

I’ve tried to use different fan control programs like Macs Fan Control or SSD Fan Control, but it seems like they can’t control the fan at all..