My Whirlpool (bottom) freezer's evaporator keeps frosting, thus rendering the (top) refrigerator warm.

Actions already taken:

  1. Replaced Defrost heater (U-shaped, stove coil-like heating element)
  2. Replaced Defrost thermostat (small "eye" looking thing, with 2 wires, and clips on the start of the cooling coil)
  3. cleaned the coils at the bottom (outside).
  4. Magnetic door strips looks fine to me.

The freezer frosts completely after around 9-days. The temperature will get extremely cold (-16C) and humidity will be around 70%, with the evaporator completely frosted.

What other things should I check?

  • 1
    Steps 1 and 2 were definitely the right move. It sounds like you are still having trouble with the defroster not activating though. Consider hooking up a volt-ohm-meter to the defrost heater terminals and placing the defrost thermostat into a cup of ice water. The ice water should cause the defrost heater to trigger and then your heating element should engage. If you do not register this on the Volt-Ohm-meter, then your issue has been isolated to an electrical problem. You may need to replace a circuit board or check continuity of the wiring for breaks. Jan 29, 2016 at 5:53
  • If you're within 2 years from the purchase, fill a warranty complain with the seller, he'll have to fix the problem or replace the fridge.
    – DDS
    Feb 16, 2018 at 13:50

1 Answer 1


Partial frosting is a common sign of loss of refrigerant pressure, i.e. a leak in your evaporative cooling system. You've already addressed the other likely causes of frosting (great!) but that leaves you with the likelihood that it's a leak (doh!).

Refrigerant chemicals are environmentally toxic and potentially hazardous, so at this point you should either have it professionally serviced or replace it (disposing of the old unit properly).

  • 1
    If the freon's leaking, it should stop cooling in no time. Right?
    – Rollo R
    Jan 28, 2016 at 1:41
  • I imagine that depends on the severity of the leak. Perhaps it was just underfilled? Jan 28, 2016 at 21:41
  • This issue would not clear up and return after a time. It would just stop working and never work again (until the refrigerant is re-charged) Jan 29, 2016 at 5:55
  • 1
    One of the problems with a system that is low on charge is icing of the lines! For those that do not know and gave down votes do some reading. @Rollo R. I repair systems all the time that are low on charge and they still cool, some leaks are so small even good detectors can not find them, but after a year or 2 another few ounces of Freon is all it takes to get rid of icing problems
    – Ed Beal
    Feb 15, 2018 at 23:34

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