Dishwasher Making Loud Noise? How to Fix it

Fred's Appliance
March 31, 2022
Dishwasher Repair

Dishwashers can make a variety of unusual and loud noises when a component is failing or being obstructed. Determining when the noise is made, what type of noise it is, and whether the dishwasher’s performance is being affected can help diagnose the issue.

Here is our list of the most common causes of dishwasher noise, with instructions for how to fix the issue.

Tip: Wear work gloves when repairing the dishwasher as you may encounter pieces of glass or other sharp objects.

Problem: Obstructed pump or damaged impeller

Symptoms: Buzzing, droning, or scraping sound, dishwasher not draining or washing properly

Depending on the type of dishwasher, it may have a single pump or a drain and circulation pump. If an item becomes stuck in the pump assembly or the pump impeller is clogged or broken, it can cause a loud buzzing or grinding sound.

If the pump impeller is damaged, it should be replaced. Depending on the type of pump, you may be able to replace the impeller or the entire pump.

Accessing the pump will usually require moving the dishwasher out and lying it on its back to access the pump underneath the dishwasher. Depending on the type of dishwasher, you may also be able to access the pump by removing the dishwasher’s kickplate (lower access panel) or the dishwasher screen in the dishwasher basin. Make sure to turn off the power and water to the dishwasher before accessing the pump.

Once you have accessed the pump, remove any debris and check the impeller for damage. Unusual pump noise could also indicate that the pump is failing and needs to be replaced.

Problem: Worn circulation pump bearings

Symptoms: Squealing or droning sound, dishes not being washed

If the circulation pump bearings have worn out, the spray arms will not receive enough water pressure to wash your dishes. Worn bearings will also make a droning or high-pitched squealing sound.

If the bearings have worn out, the circulation pump will need to be replaced. Make sure to turn the power and water to the dishwasher off before accessing the pump.

Depending on the type of dishwasher, accessing and replacing the circulation pump will usually require placing the dishwasher on its back. From there, you should be able to disconnect the pump hoses, disconnect the pump’s wiring harness, and unthread the pump’s mounting screws to remove it from the dishwasher.

Problem: Dishes not stacked correctly

Symptom: Thumping or banging during the wash cycle

If you hear a thumping or banging noise during the wash cycle, the dishwasher’s spray arm may be bumping against dishes that have not been stacked correctly. To fix the issue, make sure the spray arms can spin without hitting any of the dishes.

Problem: Loose drain hose

Symptom: Thumping during the drain cycle

If you are hearing a thumping sound during the drain cycle, it is most likely caused by the drain hose thumping against the cabinet while water is draining from the dishwasher.

To fix the issue, locate the drain hose and secure it so that it does not move excessively when water drains through it.

Problem: Obstruction in the chopper blade area

Symptom: Grinding or bumping during the wash cycle

The chopper blade is responsible for slicing up food debris so that it can exit through the drainpipe without clogging it. If an item gets stuck in the chopping blade area or a piece of the chopping blade is broken, it may make a grinding or bumping noise when the dishwasher is operating.

The chopping blade area is located underneath the dishwasher basin, close to the drain pump and filter. Accessing the chopping blade area can depend on the type of dishwasher, but it usually requires removing the bottom dish rack, bottom spray arm, and the dishwasher screen. For safety, turn off the power and water to the dishwasher before accessing the chopping blade area.

Once you have accessed the chopping blade area, remove any obstructions, and replace the chopping blade assembly if it is damaged.

Problem: Defective water inlet valve

Symptom: Squealing, buzzing, or knocking sound

The dishwasher’s water inlet valve opens and closes at various stages during a cycle. When the valve opens, it allows water into the dishwasher from the home’s water supply.

Over time, the diaphragm inside the valve can deteriorate and cause a high-pitched squealing or buzzing sound. If the valve is failing, it may also make a knocking or buzzing sound.

While the water inlet valve may make noise periodically when the dishwasher is operating, the best time to diagnose a defective valve is when the dishwasher is filling at the beginning of a wash cycle. You may also notice that the dishwasher is not getting enough water.

Accessing the dishwasher’s water inlet valve usually requires the removal of the dishwasher’s kickplate (lower access panel). Make sure to turn off the power and water to the dishwasher before removing the kickplate. When removing and replacing the water inlet valve, its hoses will need to be disconnected, as well as its wiring harness.

Problem: Worn out door hinges or cable rollers

Symptom: Squeaking or unusual noise when opening the dishwasher door

Most dishwashers have door hinges and cable rollers to allow the dishwasher door to open and close smoothly. The dishwasher door is supported by cables connected to springs, which thread through rollers.

Over time, the door hinges or cable roller components can wear out and make a squeaking or strange metallic noise when opening and closing the dishwasher door. If you are experiencing this problem, the components should be replaced to fix the issue.

Accessing the door hinges and the cable rollers will require moving the dishwasher from under the kitchen cabinet. The power and water should be turned off before moving the dishwasher. You may also need to disconnect the drain hose and water inlet line.

Once you have pulled the dishwasher out, you should have easy access to the door hinges and cable rollers on both sides of the dishwasher. If the door hinges or cable rollers are covered by a panel, it will need to be unscrewed. The components can then be disassembled and replaced as required.

If the issue is squeaky door hinges, adding some grease to the hinge may solve the issue.

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