Cordless vacuum makes a loud high-pitched whistling noise during use

Safety first: Turn OFF and remove the battery before inspection.

• Localize the sound: Run the vacuum briefly and listen around the dirt bin, filter cover, and wand connections to identify where the whistle is loudest. Then power off and remove the battery.
• Inspect gaskets: Examine rubber seals around the dirt bin, filter door, and main body. Look for cuts, flattening, or missing sections. Replace damaged gaskets.
• Check for cracks: Inspect the dirt bin and cyclone housing for hairline cracks. Replace the bin or cyclone assembly if cracked.
• Secure connections: Ensure the wand, nozzle, and accessories are fully inserted and locked. Loose joints can cause whistling and reduced suction.
• Replace worn parts: If the noise persists and you find visible damage, replace the affected plastic housing or seal with genuine Bissell parts.