Why Is My Dishwasher Making a Loud Grinding Noise? Diagnostic Guide

• Check lower tub sump filter for broken glass shards, chicken bone splinters, or toothpicks.
• Inspect rotating spray arms to ensure they are not striking dish handles or tall utensils.
• Notice whether grinding occurs during WASH circulation (middle of cycle) or DRAIN (start/end of cycle).

• Wash circulation heat pump motor ceramic bearings worn and vibrating under load.
• Drain pump impeller shaft loose or housing cavity gouged by broken glass.
• Hard food chopper blade damaged or foreign object lodged in chopper screen.

Glass shards from broken drinking cups, olive pits, or popcorn kernels drop past filter screens and wedge directly against the high-speed rotating drain pump impeller blades, creating an intense grinding clatter during drain intervals.

Dishwasher circulation pumps use water-lubricated carbon/ceramic sleeve bearings. Over years of hard water mineral exposure, seals weep, dissolving bearing grease and creating a loud roaring or grinding vibration whenever wash spray starts.

Models equipped with integrated food grinders (such as Whirlpool and GE) utilize a rotating stainless steel chopper blade over a perforated plate. A stripped blade drive spring or bent chopper teeth produces harsh metallic scraping.

A ladle handle protruding through the silverware basket or a large skillet rim in the bottom rack physically collides with the rotating spray arm on every revolution.

A partially restricted water inlet valve diaphragm or high home water pressure vibrates violently against brass pipe walls, creating a loud mechanical buzzing/grinding shudder during initial water fill.