Dishwasher Making Noise? Top 8 Reasons Why

Fleet Appliance
May 4, 2021
Dishwasher Repair

A normal dishwasher cycle includes a draining cycle at the beginning and end, a fill cycle, and a wash cycle. If your dishwasher is making abnormal noise, it is usually because a part responsible for one of these cycles is worn out. Food fragments, bits of glass, or other objects can also get stuck in one of these parts or cause a blockage that results in unusual dishwasher noise.

Follow this guide to diagnose and fix the most common reasons why your dishwasher is making strange noises.

1. Poorly Stacked Dishes

The simplest cause of dishwasher noise is that dishes or cutlery are in the way of the rotating spray arm. If you are hearing a thumping sound during the wash cycle, make sure the dishes and cutlery are stacked properly and that the spray arm can rotate freely.

2. Spray Arm

Typically, dishwashers have one spray arm, while other models may have two. Spray arms spray water and detergent around the dishwasher. Most spray arms have bearing rings and seals that can become loose or deteriorate over time. This can result in a rattling or squealing sound during the wash cycle. Spray arms should be checked for cracks, wear, and tear and to make sure they have not become loose.

3. Drain Pipe

If your dishwasher is making a thumping sound while the dishwasher is draining, the dishwasher’s external drain pipe could be loose and thumping against the back of the dishwasher. If this happens, reposition or secure the drain pipe.

4. Dishwasher Pumps

Depending on the model, your dishwasher may have a single pump responsible for draining and circulating water or two or three separate pumps. Dishwasher pumps can cause unusual noise if they become blocked or worn out. Both pumps also feature impellers, which can also cause noise issues.

Drain Pump

A problem with the drain pump usually results in a loud buzzing, squealing, or grinding sound. It should be noticeable when the dishwasher is draining at the beginning and end of a wash cycle.

Some dishwashers with a separate drain pump have a drain valve solenoid, which opens and closes during a drain cycle to stop or allow water to drain from the dishwasher. If this valve gets stuck in the open or closed position, it can result in the dishwasher making a buzzing sound.

Circulation Pump

The circulation pump is responsible for sending water through the dishwasher arms. Over time, the bearings inside the circulation pump can wear out and cause a squealing or continuous droning sound during the wash cycle. If the bearings are worn, the circulation pump will need to be replaced.

5. Impeller

Dishwasher pumps use impellers to push water through the dishwasher spray arms and to drain the dishwasher. Over time, impellers can deteriorate. Sometimes, the fins on an impeller can break, or it can become damaged due to scraping against the pump housing. Debris can also get caught in the impeller and cause unusual noise.

On some models, a pump impeller can be unscrewed from the pump and replaced. On other models, the entire pump will need to be replaced.

To check and replace the dishwasher pump(s) and impellers:

  1. Disconnect the dishwasher from the power source.
  2. Turn off the dishwasher’s water supply.
  3. Remove the bottom dish rack from the dishwasher.
  4. Unscrew the bottom access panel.
  5. Access the dishwasher pump underneath the dishwasher by pulling out the dishwasher and laying it on its back. You will likely need to disconnect the dishwasher drain line and fill line to pull the dishwasher out. Put a towel down to catch any water that may leak out.
  6. Disconnect the wire harness from the pump.
  7. Remove the pump from the dishwasher.
  8. Check the pump, impeller, and sump for any objects or wear and tear that could be causing the noise. You should be able to rotate the impeller.
  9. Replace a defective pump with a new one.

6. Water Inlet Valve

The water inlet valve controls the amount of water that fills the dishwasher. When the dishwasher begins a normal cycle, first it initiates a short drain cycle, and then the water inlet valve begins the process of filling the tub. This process usually lasts around two minutes. If you hear a loud buzzing or squealing sound at this time, it could be caused by a worn-out water inlet valve.

To check the water inlet valve:

  1. Disconnect the dishwasher from the power source.
  2. Turn off the water supply to the dishwasher.
  3. Remove the dishwasher access panel.
  4. Pull the dishwasher out and lay it on its back. You will likely need to disconnect the water drain line and fill line. Put a towel down to catch any water leakage.
  5. Locate the water inlet valve. The valve will be connected to a hose bringing water into the dishwasher and a hose that fills the dishwasher tub.
  6. Check the valve for wear and tear.
  7. If the valve seems damaged, replace it.

7. Chopper Blade

The chopper blade chops up food particles to stop them from blocking up the pump. If your dishwasher is making a grinding noise, it could be because food is stuck in the chopper blade area.  

To check the chopper blade:

  1. Disconnect the dishwasher from the power source.
  2. Remove the bottom dish rack.
  3. Unscrew the spray arm and manifold.
  4. Unscrew the pump filter and/or pump cap.
  5. Remove the chopper cover and check for debris or damage.
  6. Carefully check that the chopper blade is not loose, and remove any debris.
  7. Reassemble the dishwasher.

8. Door Latch

Some dishwashers make a beeping sound if the door is not properly closed. Check that the door is closing properly by closing it and listening for the click of the door latch. If the door latch is defective, replace it.

To replace the door latch:

  1. Disconnect the dishwasher from the power.
  2. Unscrew the outer door panel and/or the control panel to access the door switch.
  3. Disconnect the wires from the door latch.
  4. Remove and replace the door latch.

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