Hotpoint Mistral Fridge/Freezer. Fridge at +19 deg. cent?

I renewed the 2 thermostats about 3 years ago. Recently, there has been a very loud noise from the 'fridge compartment, which disappeared when the door opened and started again when the door was shut. The temp. was ok at +4 deg. cent. For the last 24 hours all has been quiet, but the fridge is now at +19 deg. cent., with the freezer normal at -22 deg. cent. I suspect that a fan has given up the ghost? If I am correct in my assumption, are these fans freely obtainable; also are they easy to fit?

Any help gratefully received!