Sub-Zero refrigerators make normal operating sounds, but a sound that is new, louder than before or paired with poor temperature deserves attention. Buzzing, clicking, rattling, vibration, humming and fan noise can come from different systems.
Does it stop when a door opens? Happen only during ice fill? Repeat every time the compressor tries to start? Change when the unit warms up? Timing often identifies the system making the noise.
Fan noise
An evaporator or condenser fan can buzz, scrape, rattle or grind if the motor is failing, the blade is damaged or ice is contacting the blade. If a noise stops when the door opens, a compartment fan becomes an important suspect on models where the fan stops with the door switch.
Ice contacting a fan
Frost or ice buildup can reach a fan blade and create a repetitive ticking or grinding sound. In that case the noise is only one symptom; the reason for the ice buildup also has to be diagnosed.
Compressor hum or clicking
A compressor normally makes operating sound, but repeated clicking, failed starts or a new harsh hum can involve the start relay/overload, electrical supply or the compressor itself.
Ice maker and water-valve sounds
Ice harvest and water fill create normal intermittent sounds. A buzzing valve with no water, repeated fill attempts, grinding or a new sound paired with no ice can point toward a water-supply, valve or ice-maker problem.
Rattling or vibration
Panels, tubing, a fan shroud or another component can transmit vibration through the built-in cabinet. The exact source should be isolated rather than replacing a compressor just because the noise is near the machine compartment.
Sizzling or crackling
Some sounds can occur during normal defrost operation when moisture contacts a warm defrost component. The sound is more concerning when paired with smoke, electrical odor or an abnormal temperature condition.
What to note before service
- Which compartment or machine area the sound comes from.
- Whether opening a door changes the sound.
- Whether temperature is normal.
- Whether the sound appears during ice fill or harvest.
- Whether the compressor is trying repeatedly to start.
For diagnosis, see Sub-Zero Repair.