From time to time, you may hear strange and somewhat loud noises coming from your kitchen intermittently and even in the middle of the night. Most likely you don't have ghosts or burglars. It's probably just your ice maker. Ice makers, which are typically located in the freezer compartment of your refrigerator, can make some serious noise. But there is usually a good explanation for it. Also, it's usually not a cause for alarm or an indicator of needed repairs.
If you hear a loud hissing sound coming from the vicinity of your freezer, it is most likely your ice maker making the racket. An ice maker works by filling cube molds with water, giving them time to freeze and then dumping the cubes out and refilling the molds. The hissing sound you hear from the freezer is the sound of the water shooting through the supply line and into the molds. If the water is turned on all the way at the connection, as it should be, the water will come through with a bit of force and cause this hissing sound, which is perfectly normal for an ice maker.
Crash and Tumble
One of the most sudden and unusual sounds you'll hear from your ice maker is a crashing or a tumbling sound. It may even sound like someone is inside the freezer dumping a bucket of rocks out of one bucket and into another. The reason this muffled crash happens is similar to that, actually. When the cubes freeze in the molds, the ice maker ejects the cubes into a catch bin so the ice doesn't fly all over the freezer compartment. It keeps it all in one neat spot. If the catch bin is empty when the ice cubes dump in, the noise will be even louder.
Snapping or Clicking
When the ice maker dumps the fresh ice into the bin, it immediately calls for more water to refill the molds to make another batch. When the ice maker makes this demand from the water line, there is a distinct snapping or clicking sound that may sound like a problem to someone not used to it. It is actually a normal sound and will likely be followed closely by the hissing sound described in Section 1.
A loud ticking sound, a loud hum or other unusual noise may originate from an ice maker that is connected to power but not hooked up to a water source. For the ice maker to work properly, it must have a water line connection that is turned on. Otherwise, the noise will result from the machine trying to get water and having none available to it.