Frigidaire EFWC498 Notice D'utilisation page 6

The water cooler seems to make to
much noise
The rating noise may come from flow of the
refrigerant, which is normal.
As each cycles ends, you may hear gurgling.
Sound cause by the flow of refrigerant in your
water cooler.
Contraction and expansion of inside walls may
cause popping and cracking noises.
The water cooler is not level.