Not cooling · Is the refrigerant going?
Is Hissing or Gurgling a Leak, or Normal?
- Signed
- Dean Halvorsen
- Role
- Refrigeration technician — sealed systems and airflow
- Certification
- EPA Section 608 certified
- Published
Short answer
Usually normal. Sub-Zero puts gurgling and hissing down to defrost water draining away, a drain tube that is partly blocked, or the evaporator simply working. A sound matters when it is new, grows louder or never stops, and more so when the unit is warming too. Sub-Zero Repair Edmonds can trace it: (206) 210-3547.
Sounds a working Sub-Zero makes
- Gurgling, trickling or hissing. Sub-Zero traces these to water draining during the defrost, a drain tube that is partly plugged, or the evaporator (the cold coil inside each section) doing its job. An older Sub-Zero owner’s guide also describes a running-water sound as refrigerant moving through the tubing.
- Sizzling or crackling. Moisture meeting the defrost heater while it clears frost.
- A hum, or a moment of vibration as the compressor starts or stops.
When a sound earns a visit
Sub-Zero’s rule is simple: a noise that is new, keeps getting louder or never goes away may need service. Add a fourth case: any sound that arrives while the unit is also warming, or alongside an oily spot on tubing.
One cause you can help with. Sub-Zero notes that a warmer setting may stop water freezing in the drain tube, and recommends 38°F in a refrigerator and 0°F in a freezer. If yours is set colder than that, set it back.
On the visit the drain and the fans are checked, and pressures are read only if the unit is warming as well.
What it may cost
$89 to find out — the visit and the diagnosis, taken off the repair if you go ahead.
Most of these sounds need no repair. A blocked drain tube is quoted after the diagnosis; a leak confirmed on gauges falls in the sealed-system range.
Ranges, not starting prices. The technician names one figure inside the band before any panel comes off, and Sub-Zero Repair Edmonds holds to it.
Wait or call today?
Can wait until morning
- The sound comes and goes with the unit's cycles and both sections are holding their temperatures.
- It gurgles or sizzles for a spell and then falls quiet, which fits defrost water or the heater at work.
Call today if
- A new noise has turned up together with warmer shelves or a softening freezer.
- The noise comes with a burning smell: switch off at the breaker first, then call.
- Water is pooling on the compartment floor or under the unit.
Anything in the second card is a reason to phone Sub-Zero Repair Edmonds on (206) 210-3547 today rather than tomorrow.
Questions people ask next
Does hissing mean the refrigerant is escaping?
Not on its own. Sub-Zero files hissing alongside gurgling, with the same everyday causes. A leak becomes a real possibility when a steady new sound arrives while the food slowly warms, and gauges settle it either way. If both are happening, call Sub-Zero Repair Edmonds on (206) 210-3547 rather than waiting to see whether the noise stops.
Could the cabinetry be making it louder?
It can. An older Sub-Zero owner's guide points out that walls, floors and nearby cabinets change how loud a unit sounds, and a built-in stands inside a box of them. A sound that seems new after a kitchen remodel may be an old, normal one carrying further, though a technician can confirm that on the visit.