A refrigerator makes a variety of different noises during operation and this is normal. This mostly due to the product maintaining its temperature setting. The noises may come from a variety of different sections of the product like the compressor, the fan or even the cooling refrigerant. If you have any further concerns, please be with your product and contact Hisense Customer Support on 800 447 367. Hours of operation are Monday to Friday 8:30am to 7:30pm AEST and weekends from 9am to 5pm AEST.