I have a bottom freezer refrigerator. The left side of the evaporator coil in the freezer section ices up, which does not allow air to circulate between the refrigerator and freezer. This results in no cooling in the refrigerator section and thus, food spoils. To fix the problem, we need to remove the inside panel of the freezer and unfreeze the ice on the evaporator coils with a hair dryer. This has happened 4 times in the past year and a half. The seals around the freezer door and refrigerator door are in excellent shape, as room air temperature is not getting into the refrigerator or freezer through the seals. The refrigerator is in excellent condition and we are frustrated that we cannot figure out why the evaporator coils in the freezer section keep freezing up approximately every 4 months. Does anybody know what can be done to fix this reoccurring problem and prevent it in the future.