A refrigerator is the only appliance in the house that never switches off, which is why people notice its noises. Most of those noises are the machine working correctly. Three of them are worth a phone call.
Here is the whole vocabulary.
Normal, and you can stop worrying
Gurgling and trickling, usually a few minutes after the compressor stops. That is refrigerant equalising through the system. It is meant to happen.
A soft hum that comes and goes, lasting anywhere from twenty minutes to a couple of hours. That is the compressor cycling. Newer inverter compressors run almost continuously at low speed and are quieter but more constant — if you replaced an old refrigerator recently and it now seems never to stop, that is usually the reason.
Popping and creaking, especially at night. Plastic liners and metal shelving expanding and contracting as the compartment cycles through its temperature range.
A sizzle or hiss every eight to twelve hours, sometimes with a drip. That is the defrost heater melting frost off the evaporator coil and the water running to the drain pan. It should last twenty to thirty minutes.
A rush of water followed by a rattle on a model with an ice maker. The valve filling the tray, then cubes dropping.
Worth investigating
A fan noise that has got louder. There are two fans — the evaporator fan in the freezer and the condenser fan underneath at the back. A bearing going dry in either produces a whirr that grows over weeks.
The evaporator fan is the one to care about. If it stops, the fridge compartment warms while the freezer stays cold, because the cold air has no way to travel. Open the freezer and listen: the fan should stop when you open the door and start when you press the door switch.
A rattle or buzz from the back at floor level. Usually the condenser fan catching on something, or a drain pan that has shifted. Unplug the appliance, pull it out, and look. Dust and pet hair build up on the condenser coil down there and are worth vacuuming twice a year regardless — a clogged coil makes the compressor work harder and shortens its life.
Clicking every few minutes, with no cooling. This is the start relay trying to start the compressor and failing. The compressor draws current, the overload protector cuts in, everything rests, and the cycle repeats. The relay is a cheap part and a same-visit repair if it is caught early. Left alone, the repeated stalling can damage the compressor itself, which is not cheap.
Stop and call somebody
A loud rumble or knock from the compressor that is new. A compressor is a sealed unit; there is nothing to tighten. A knock means internal wear, and on most domestic refrigerators the sensible answer at that point is replacement rather than repair. We will say so.
A sharp scraping from the freezer. That is the evaporator fan blade hitting a build-up of ice. There is a defrost fault behind it, and it will not fix itself — the ice grows until the fan seizes or the blade snaps.
Any burning or electrical smell. Unplug it. This is not a wait-and-see.
The diagnostic nobody thinks of
Before assuming a fault, check whether the noise changes when you open a door.
Open the freezer. If the noise stops, it is the evaporator fan, because the door switch cuts it. If it continues, it is coming from the compressor compartment at the back.
That single test narrows a service call from the whole appliance to one of two areas, and it is the first thing our technicians ask about on the phone.
Where the ice maker fits in
Ice makers are responsible for a disproportionate share of refrigerator noise complaints, and almost all of it is normal. Filling, harvesting, cubes dropping into a plastic bin — it is a loud sequence happening several times a day.
The one that is not normal is a grinding that repeats without any ice appearing. That is usually the harvest motor fighting a jam, and ice maker repair is its own small job.
The summary
Gurgle, hum, pop, hiss: leave it alone. Fan noise that is getting worse, or clicking with no cooling: worth a call soon, because both are cheap now and expensive later. Compressor knocking, scraping ice, or any smell: stop.
If you are not sure which one you have, ring (617) 685-8530 and hold the phone near it. We can usually tell you from the sound, and we would rather do that than charge you for a visit you do not need.
