Dishwasher Making Noise? The Different Noises Explained

November 2, 2022
Dishwasher Repair

It’s always worrying when an appliance starts to make a strange sound, but don’t panic! Our easy-to-follow article will help you to identify what the weird noise from your dishwasher means, and how you can fix the problem. 

Beeping Noise

A beeping usually means that your dishwasher is trying to indicate that it is experiencing an error. Check the display panel to see if an error code is being displayed. You can consult your user manual to see what the error code means and how it can be solved. 

Grinding Noise

There are a couple of different causes of a dishwasher making a grinding noise. 

Something is stuck in the pump or chopper blade of your dishwasher

The chopper blade of the dishwasher is there to cut up debris to allow it to go through the drain without causing blockages to your pipes. Occasionally, a hard piece of food such as a nut or a popcorn kernel, or a bit of non-food debris like a piece of broken crockery can get stuck in the chopper mechanism.

To fix this:

  • Turn off the power to your dishwasher.
  • Remove the bottom dish rack (including the spray arm and dishwasher screen) in order to access the chopper blade. Please note that the location of the chopper blade may differ in some makes and models, so if you are unsure where yours is located, make sure you have a look at your user manual. 
  • Once you have found the chopper blade, remove anything that is obstructing it. If the mechanism itself is bent or damaged in any way, you will need to order a replacement part from your dishwasher manufacturer. 
  • Once you have unblocked the chopper blade or replaced the blade, your dishwasher should no longer be making the grinding noise.

Your dishwasher is running with insufficient water

A dishwasher running with insufficient water can also cause it to make a grinding noise. To check this, try opening your dishwasher at the beginning of the wash cycle after it has finished filling. If there is very little water, the issue is likely with one of the following two parts:

Obstructed overflow protection float

The overflow protection float signals to the dishwasher when it has filled with sufficient water. If something like a dropped utensil is obstructing the float, it could be preventing your dishwasher from filling. 

To check if this is the problem:

  • Locate the overflow protection float. This is usually in the front right corner, but if you can’t see yours there, check your user manual to help you locate it. 
  • Check that the float is unobstructed and that it can move easily up and down. If there was an obstruction, removing it should solve your issue. If you couldn’t find anything wrong, the issue is probably your water inlet valve.

Defective Water Inlet Valve

The water inlet valve opens and closes to allow water into the dishwasher. Over time, the part can start to degrade, which will initially make a high-pitched sound and can progress to a knocking or grinding sound. If the valve is damaged, you will need to order a replacement part as they can’t be repaired. 

To access the inlet valve:

  • Turn off the power and water supply to your dishwasher. 
  • Remove the lower access panel. 
  • Locate the water intake valve, using your user manual to help you find it. 
  • Disconnect the water inlet valve from the water supply and from its wiring harness. You can now install a new replacement part in its place. 

High-Pitched Noise or Buzzing Noise

This usually indicates a problem with the circulation pump, namely that the bearings are worn out. If this is your issue, you will have noticed that your dishes are not being washed properly. If the circulation pump is the problem, it will need to be replaced. You can order a replacement part from your dishwasher manufacturer.

To replace the circulation pump:

  • Disconnect your dishwasher from the power and the water supply. 
  • Carefully place your dishwasher on its back.
  • Once you have located the circulation pump, you will need to remove it from the water supply hoses as well as remove it from its wiring. 
  • You can now install the new circulation pump in its place. 

Knocking or Rattling Noise

There are two main reasons a dishwasher might make a knocking sound when it runs.

Improperly stacked dishes

If your dishwasher is stacked incorrectly, the knocking sound will be caused by the spray arm hitting the utensils as it spins. This is a very easy fix – simply ensure that the spray arms are able to fully rotate before you begin your wash cycle. You may need to make sure you position the larger items at the edge of the dishwasher so that they do not obstruct the spray arms.  

Make sure to check the spray arm at the bottom of the machine too – sometimes part of a dish or utensil can be sticking through the rack and preventing the bottom spray arm from spinning.  

Loose drain hose

If your drain hose is not secured properly, when the dishwasher is draining it can move around and thump against the side of the machine as the water goes through it. This is another easy fix – you can simply use cable ties to secure the hose and eliminate the problem. 


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