The part(s) or condition(s) listed below for the symptom Dishwasher making noise are ordered from most likely to least likely to occur. Check or test each item, starting with the items at the top of the page.
The circulation pump motor has bearings that wear out over time. When the motor bearings fail, they generate a continuous drone. If the motor bearings have failed, you must replace the entire circulation pump.
The wash impeller is a small plastic blade that forces water through the spray arms. If one or more of the impeller blades is broken, the dishwasher will make noise. In addition, if the impeller is damaged, warped, or bent, it can scape against the pump housing. Inspect the wash impeller for damage. If the wash impeller is damaged, replace it. On most models, you can replace the wash impeller independently of the pump and motor assembly. Search for your model number to determine if your impeller is replaceable. If the impeller cannot be replaced separately, you will have to replace the entire pump and motor assembly.
The water inlet valve opens to allow water to enter the dishwasher. When it is new, the water inlet valve is very quiet during operation. Over time, the diaphragm inside the valve deteriorates and deforms. This deformation interacts with the water rushing in and can produce a loud vibration, buzzing, squealing, or other noises. If the dishwasher is loud during the filling cycle, replacing the water inlet valve may solve the problem.