Describe the rhythm
Say whether it changes when the door is opened and whether drawers or packages were recently repositioned. Keep an existing brief recording if available.
Assessment with boundaries
An engineer may need to inspect accessible fans or defrost-related components on a suitable model. Do not remove internal panels; sealed refrigeration work is not offered.
A useful distinction
A fan contacting ice and a loose drawer vibrating can sound alike through an insulated cabinet. Location and the relationship to the door help decide what to inspect, without selecting a fan assembly in advance.