Diagnosis
A foreign object—like a small toy, pebble, or large clump of dust—is almost certainly lodged in the amplifier loop at the back of the machine, interfering with the oscillation gear.
How to Fix It
Stop oscillation immediately. Inspect and clear the loop aperture.
- Turn the machine off and unplug it.
- Look directly into the narrow, circular opening at the rear of the loop (where air is projected from). Use a bright flashlight.
- If you see debris, use a long, thin, non-metallic tool like a plastic coffee stirrer or a cotton swab with the cotton removed to gently dislodge and extract it. Do NOT use metal.
- Manually rotate the loop by hand to check for smooth movement.
If That Didn't Work
The noise is internal. The plastic gear train for the oscillation mechanism has likely worn down or a tooth has broken. This requires a full parts replacement by Dyson service.
Heads Up
This is a common result of not cleaning the rear filter regularly. A heavily clogged filter strains the motor and can cause vibrations that feel like grinding. Clean the filter monthly.