Amana AFB2534DE Bottom Freezer French Door Refrigerator "bg21" Questions

I have an Amana BG21 Firdge. It has been making a lot of noise for the past month. Noise is gone and fridge isn't very cold. Is it inexpensively fixable? The noise is most likely the evaporator fan ...

coils freezing up we have a BG21 bottom freezer refrig. and the coils in the back of the freezer are frosting up and we have to thaw them out about every 3rd month. any suggestion on what the problem ...