there's a loud rattling or buzzing noise coming from inside the fan, especially on higher speeds.

Diagnosis

The rattling or buzzing noise in the Vornado OSCR37 is typically caused by a mechanical interference between the rotating impeller (the cylindrical fan blade assembly) and the internal housing. Because this model uses a blower-style cylinder rather than a traditional blade, even a millimeter of shift in the assembly can cause the blades to graze the plastic walls, creating a high-frequency buzz that intensifies as the RPMs increase on higher speed settings. In many cases, the root cause is a displaced internal foam sound-dampening liner. This black acoustic foam is glued to the inner walls of the plastic chassis to reduce wind noise; however, over time or due to heat, the adhesive fails. When a piece of this foam peels away, it hangs into the path of the impeller, creating a rhythmic "tapping" or "rattling" sound that sounds like a foreign object is stuck in the motor. To confirm this, switch the fan to its lowest speed. If the noise is a faint hum but becomes a violent rattle at speed 3, it is almost certainly a clearance issue or a loose internal component. If the noise persists even when the oscillation is turned off, the issue is centered on the impeller axis rather than the oscillation gears.

How to Fix It

To resolve this, you must gain access to the internal blower assembly to clear debris or reseat the dampening materials.

1. Disconnect the power cord from the wall outlet completely to prevent accidental startup.
2. Lay the fan face down on a soft surface to avoid scratching the exterior plastic.
3. Locate the rear grille assembly. Using a Phillips #2 screwdriver, remove the screws securing the rear panel. Be careful not to strip the plastic housings, as they are soft.
4. Carefully pull the rear grille away from the main body. Reach inside and visually inspect the cylindrical impeller. Look for any foreign objects—such as plastic packaging tags, hair clumps, or small debris—that may have been sucked into the intake.
5. Inspect the inner perimeter of the plastic housing for peeling strips of black foam. If you find a loose flap of foam, do not simply tear it off. Use a small amount of high-temperature contact cement or a dab of superglue to secure the foam firmly back against the wall of the housing.
6. Manually rotate the impeller by hand for one full 360-degree turn to ensure there is no physical contact with the walls or the foam.
7. Reinstall the rear grille and tighten the screws firmly but do not over-tighten, as this can warp the plastic and actually create new rattles.

If That Didn't Work

• Check the Impeller Nut: The central nut holding the blower cylinder to the motor shaft may have loosened. If the cylinder is wobbling slightly on its axis, it will rattle at high speeds. Use a socket wrench to ensure the center nut is snug, preventing the "axial play" that causes the vibration.
• Inspect the Oscillation Base: If the noise only occurs while the fan is moving side-to-side, the issue is likely the oscillation gear assembly at the bottom. Check for a loose screw in the base plate or a dry gear. Apply a small amount of white lithium grease to the oscillation pivot points to eliminate mechanical grinding.
• Verify Level Surface: The OSCR37 has a high center of gravity. If the floor is uneven, the entire chassis can vibrate against the floor surface, mimicking an internal rattle. Place the fan on a hard, level surface or use rubber anti-vibration pads under the base to isolate the motor frequency.
• Motor Bearing Failure: If the noise is a metallic grinding sound rather than a plastic rattle, the motor bearings may be failing. If the impeller feels "gritty" when turned by hand while unplugged, the motor is reaching the end of its lifespan and cannot be serviced.

Heads Up

• Avoid using compressed air cans to clean the interior; the high pressure can actually push debris deeper into the motor windings or displace the foam liners further.
• Never operate the fan with the rear grille removed, as the impeller is exposed and can cause injury or suck in loose fabrics.
• Periodically vacuum the intake vents at the rear. Dust buildup on the impeller blades creates an imbalance, which leads to the very vibrations and rattles you are trying to fix.
• If you apply adhesive to the foam, let it cure for at least 2 hours before plugging the fan back in to ensure the glue has bonded and won't fly off into the motor.