Robot vacuum making loud or unusual noise — diagnostics and repair in Riga

Likely causes

• Worn BLDC motor bearings — high-pitched whine — The brushless BLDC motors in robot vacuums rely on bearings as their primary wear component. After 1,500–2,500 hours of operation, the bearing balls and races lose their original precision, producing a characteristic high-pitched whine that intensifies at maximum power. The noise typically builds gradually, becoming more pronounced each week. Continued use with worn bearings can cause the rotor to seize and the motor to fail completely.
• Cracked or broken impeller fan blade — If a hard object — a pebble, coin, or toy fragment — enters the robot, the plastic impeller fan blade can crack or lose a section. The resulting imbalance manifests as vibration, rattling, and irregular knocking, particularly at higher RPMs. A damaged impeller also reduces suction power and can cause secondary bearing damage due to the increased vibration transmitted through the motor shaft.
• Loose or worn brush module — The main brush and side brushes are held in place by plastic clips and bearings. Over time, these clips can loosen and the brush-axle bearings can wear, causing the brush to vibrate or spin with an uneven rhythm that produces a knocking or clicking sound. The problem is often aggravated by hair and thread wound around the brush axle, creating additional friction and noise.
• Debris in wheel cavities — clicking and rattling — Hair, dust, small objects, and pet fur accumulate in the cavities of the drive wheels and the front caster wheel. This debris interferes with free wheel rotation, creating a knocking, squeaking, or clicking sound that is amplified on hard flooring surfaces. The issue is especially common in homes with pets and is one of the simplest noise causes to resolve.
• Damaged suspension spring — persistent rattle — Many robot vacuum models feature suspension springs in the main brush module or the wheel mounts that absorb vibrations and ensure consistent floor contact. If a spring breaks or deforms, the robot develops a persistent rattle and vibration, especially on uneven surfaces or when transitioning from carpet to hard floor. This sound differs from motor noise — it is lower-pitched and more irregular.
• Clogged air path — whistling or hissing sound — When the air channel between the brush chamber, dustbin, and motor is partially blocked by dust, hair, or small objects, airflow forced through narrow gaps creates a whistling or hissing sound. The noise intensifies at maximum power when airflow velocity is greatest. A complete blockage can turn the whistle into a loud howling or droning sound.

What you can check yourself

1. Run the robot without the main brush — remove the brush and start the robot to determine whether the noise comes from the motor/fan or the brush module. If the noise disappears without the brush, the problem is in the brush or its bearings.
2. Turn the robot upside down and check both drive wheels — pull each wheel out and clean the cavity of hair, fur, and debris. Spin the wheels by hand — they should rotate freely and silently.
3. Remove the dustbin, open the cover, and visually inspect the impeller fan through the air channel — look for cracks, broken sections, or foreign objects. Never insert your fingers into the motor.
4. Test the robot on different surfaces — run it on hard floor and then on carpet. If the noise appears only on one surface, the issue may relate to suspension or brush-to-floor contact.
5. Clean all filters — remove the HEPA filter, tap it out over a bin, and, if it is washable, rinse it under water. A clogged filter increases motor load and can amplify noise.

When to bring it in

Affected brands

Frequently asked questions