1. Check the pre and post motor filters for debris. Failure to properly maintain the filters could damage the motor. A clogged hose may also cause the unit to sound loud; see our “Clearing Clogs” FAQ for details.
2. If this doesn’t work and the vacuum still makes a lot of noise, please take your vacuum to a technician. You can find your nearest BISSELL® Authorized Service Center by clicking http://www.bissell.com/support/product-support/service-centers or by calling 1-800-237-7691, available 24 hours a day.