Many dishwashers are specifically designed to operate quietly, but some noise during operation is to be expected. However, if the dishwasher is making a vibrating noise that is loud and unusual, there may be some basic causes that may be at fault. It is worthwhile to attempt some troubleshooting before contacting a service professional for assistance.
Make sure the dishwasher is installed on a surface that can support the weight of the appliance and is flat. A weak floor surface can result in a loud vibration noise during operation. If necessary, move the dishwasher to another location or place a 3/4-inch piece of plywood under the unit for additional support. Check the drain hose and make sure the hose is not trapped or knocking against the cabinet or dishwasher.
A vibrating noise may result if a utensil or other small, hard object falls down from the dishwasher racks and is vibrating on the floor of the dishwasher during use. Turn off the dishwasher and open the bottom rack. Inspect the dishwasher bottom for any items that may have fallen and remove as necessary.
Many dishwashers have a filtration system in the bottom of the tub, and if large food chunks or other debris fall into the filter, it may make a loud vibrating sound. Turn off and open the dishwasher. Remove the bottom rack and lift the top housing off of the filter, using a spoon or other utensil if necessary. Clear out any hard or large objects from the filter, rinse the filter with water and replace. The dishwasher may also have a hard food grinder installed, which may make noise when grinding up food debris. This is normal and will go away once the item has been sufficiently ground up and disposed of through the dishwasher drain system.
Avoid overloading the dishwasher, as dishes, pots or pans or lids that are touching during the wash process may create a vibrating noise. Leave space between each dish and make sure the spray arms can rotate freely. Secure light items in racks on the upper rack and lean large items such as pots or pans forward toward the center of the dishwasher rack to keep them from rattling against the dishwasher walls.
Meredith Jameson writes early childhood parenting and family health articles for various online publications. She holds a Bachelor of Arts in history from San Francisco State University.