Refridger is randomly making odd, loud, humming, fan like noise with periods of silence in between. I have unplugged and replugged the fridge in as well as inspect the back. (No visble coils/vents, as it is all sealed) it seems like  it's the fan located in freezer section, maybe compressor??

Not sure of age of fridge, as it was here when I moved in three years ago. Previous homeowner had no context. Thanks!