Frost contained by my fridge??? I have a kenmore top freezer and bottom fridge component. every two...

I have a kenmore top freezer and bottom fridge component. every two months of so the top freezer portion starts to have frost come out of the inside stern of the vents located at the final of the freezer. When I let it verbs the frost gets SOOOOO unpromising that it actually prevents the bottom fridge from working and stops cooling altogether. When I unplug and agree to the unit defrost... the fridge and freezer appear to get adjectives better and work FINE. My father thinks that the self defrost workings of the fridge in out/broken and suggests that I call for a repairman to simply replace it. what do you think. How much to fix. and should I freshly call SEARS????
My house be flooded by the river, how...
Answers:    your freezer may be to cold. within should be a switch, or a dial that you can turn to change the heat.
There may be a problem beside the vent...
Is it still under warranty? Some unit have a longer warranty on the refrigeration bit of it, then telephone call Sears. Most independents are cheaper than Sears. Yes the self defrost is probably on the blink. Probably the heating part.