Some designs change fan operation when the door opens. The change can help describe the sound, but it does not by itself confirm which component needs repair.
What the observation tells you
A door sensor affects several functions on some appliances. Holding it closed artificially or removing a panel to expose a fan is not an appropriate household test. Scraping, persistent vibration or poor cooling still needs attention even when the sound stops with opening.
A useful next step
Report that normal door opening changes the noise and include any temperature or frost observations. Keep the door closed between ordinary checks so the investigation does not unnecessarily warm the contents.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.