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Sub-Zero Refrigerator Making Loud Noises? Here’s Why…

In this Article

Sub-Zero refrigerator making loud noise

Part of a Sub-Zero’s superior cooling technology is its near-silent operation. So, why is my Sub-Zero refrigerator making loud noises? An evaporator fan blade may be damaged or obstructed, causing a knocking sound. Learn how to troubleshoot loud refrigerator noises to restore your Sub-Zero’s silence.

4 Reasons for a Sub-Zero Refrigerator Making Loud Noise

Evaporator fan, compressor or condenser issues are usually responsible for a Sub-Zero refrigerator making loud noise. Since Sub-Zero refrigerators have separate evaporator fans for the refrigerator and freezer, how can you determine which fan is responsible?

Open the freezer and refrigerator doors. If the sounds continue after closing the refrigerator doors, the refrigerator evaporator fan is at fault. If you still hear loud noises when the freezer door is shut, the issue lies with the freezer’s evaporator fan. Here’s how to pinpoint the specific problem that causes loud sounds.

Sub-Zero refrigerator compressor noise

Image Courtesy of Sub-Zero

Damaged or Obstructed Fan Blade

An evaporator fan blows cool air over the evaporator coils to help cool refrigerant. If a fan’s blades are obstructed or damaged, they may not rotate completely or at all. When this happens, you may find your Sub-Zero refrigerator not cooling sufficiently. If the fan blade is blocked you may also hear your Sub-Zero refrigerator making knocking noise. 

Sub-Zero recommends that a professional repair service access the fan to assess the blades and remove any blockages.

Failed Fan Motor

If the evaporator fan blades aren’t obstructed it’s possible that a Sub-Zero refrigerator making loud noise is caused by a failed fan motor.  As previously mentioned, this noise will get louder when the refrigerator or freezer door is opened. A failed fan motor can’t be repaired and should be replaced by a professional service.

Accumulated Ice

Sometimes, ice can accumulate on evaporator fan blades, resulting in a Sub-Zero gurgling noise. This often occurs if there’s a defrost system malfunction that allows moisture to linger and freeze. Since the evaporator fans are each located behind a refrigerator or freezer panel, you likely won’t see the ice on the fan blades. However, accumulated ice on the rear freezer or refrigerator wall may be visible.

If there is a buildup of ice on the walls, consult your user manual to determine how to manually defrost the refrigerator. While this may get rid of the ice, it will reaccumulate if an underlying defrost system issue persists. A professional service should assess the defrost system for malfunctions.

Compressor or Condenser Malfunctions

The refrigerator’s compressor and condenser components are essential to its function. The compressor circulates refrigerant by controlling its pressure. The condenser coils and fan help keep the refrigerant cool so it can create cool air for the refrigerator. 

A Sub-Zero refrigerator making loud noise may be due to the following compressor or condenser issues:

  • Dirty Sub-Zero refrigerator coils: If the condenser coils are covered in dirt or debris they may not sufficiently cool the refrigerant. This forces the compressor to work harder, often resulting in louder noise. Check your user manual to determine how to clean the condenser coils on your model refrigerator. Most are located behind an upper grille and can be easily cleaned with a vacuum’s brush attachment or appliance brush.

Sub-Zero refrigerator making rattling noise

Image Courtesy of Sub-Zero

  • Condenser fan malfunction: A condenser fan helps cool refrigerant as it flows through the coils. A Sub-Zero refrigerator making a rattling noise often has a broken or obstructed condenser fan blade or failed fan motor. The refrigerator will also struggle to maintain its temperature if the refrigerant isn’t properly cooled. A malfunctioning condenser fan requires professional replacement.
  • Failing compressor: Sub-Zero refrigerator compressor noise should normally sound like a low hum. However, if the humming noise increases in volume, it’s possible that the compressor is failing. While it may continue to operate for a period of time, a failing compressor should be professionally evaluated.

The professionals at Don Bacon Appliance can silence any loud refrigerator sound. Contact us for the very best Sub-Zero appliance repair Cincinnati.

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