Dishwasher Making Loud Noise

Rattling — Items Not Loaded Correctly

The most common cause. If items in the racks are loose or poorly positioned, they will rattle against each other or the spray arms. Ensure all items are loaded securely and that taller items are not blocking the spray arms from rotating.

Thumping — Spray Arm Hitting an Item

If a spray arm is catching on an item in the rack during rotation it will produce a regular thumping noise. Check that nothing is overhanging the racks and obstructing the spray arms’ rotation.

Grinding — Foreign Object in Filter or Pump

A grinding or crunching noise usually indicates a foreign object — broken glass, a bone fragment or a label — that has made its way into the filter or pump area. Clean the filter and check the pump housing carefully.

Loud Humming or Buzzing — Inlet or Pump Issue

A loud constant hum or buzz can indicate the water inlet valve is struggling to open, the circulation pump is partially blocked, or the drain pump is running against a blockage. Requires professional investigation if cleaning the filter does not resolve it.

Squealing — Worn Pump Bearings

A high-pitched squeal during the wash phase can indicate the circulation pump bearings are worn and the pump is beginning to fail. This requires professional diagnosis and pump replacement.

Knocking During Drain — Hose Siphoning

A knocking or banging sound during the drain phase can be caused by the drain hose siphoning water back into the machine. Ensure the drain hose is correctly positioned and not inserted too far into the standpipe.

Check the Loading

Remove all dishes and reload carefully. Ensure nothing is overhanging the racks and that the spray arms can rotate freely. Secure lightweight items such as plastic containers so they cannot move during the cycle.

Clean the Filter

Remove the filter assembly and clean it thoroughly. Check the area around the filter and pump housing for any debris, broken glass or foreign objects that may be causing the noise.

Check the Spray Arms

Remove the spray arms and check they are not cracked or blocked. Ensure they refit correctly and spin freely without catching on anything in the tub.

Check the Drain Hose Position

Ensure the drain hose is not inserted too far into the standpipe and that it has a high loop to prevent siphoning. A correctly positioned hose eliminates knocking during the drain phase.

Reset the Machine

Switch the dishwasher off at the mains and leave it unplugged for a few minutes. Plug back in and run a cycle to see if the noise persists after the above checks.