Dishwasher Making Grinding, Humming or High-Pitched Noise?

Dishwashers have valves and motor, so it’s normal for them to make some noise when running.

But that doesn’t mean that the sound should be too loud to interfere with conversations.

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Strange or unusually loud dishwasher sounds are usually an indication of technical issues that you should attend, too, lest they pile up and cost you some freaking good amount of money to repair.

So, how do you solve your dishwasher noise problem? Here’s a breakdown of why your dishwasher may be making grinding, rattling, humming or high-pitched noises:

Dishwasher making grinding noise

Some dishwashers make grinding noises as they go through a cycle.

And sometimes, this noise is normal if the dishwasher’s electronic control panel has a motor-driven switching device, but the grinding shouldn’t be too loud.

If the grinding suddenly gets too loud, inspect the dishwasher because the cause could be:

a) A foreign object has stuck inside the pump or chopper blade area

Typically, the cause of grinding noises is a foreign object stuck inside the rotating plastic blades of the dishwasher.

This could have happened during cleaning; a hard food item or piece of the dishes broke and fell straight into the bottom of the machine then got lodged around the dishwashers drain impeller.

If you hear odd grinding or vibrating sound from your dishwasher during a cycle, just open the dishwasher’s door, allow the steam to dissipate then pull out the bottom rack and inspect for any dish parts, food items, glass, etc. in the pump or chopper blade area of the dishwasher.

Start by unplugging the dishwasher from the outlet. Next, remove racks from the dishwasher to access the bottom and unscrew the lower spray arm unit off.

Look for any debris and get rid of it then continue removing part to get to the bottom of the machine.

The next component you are going to remove is the dishwasher screen, located beneath the lower spray arm.

Check for debris then ensure you clean the filter with water and soap to remove food grease.

Next, move to the pump housing cap, the plastic housing that covers the rest of the dishwasher’s internal components.

Check for debris or chinks of food in the food disposer blade.

Now you have reached the very bottom of the dishwasher; this is where most food items and debris go.

Unscrew the upper impeller to reach the food grinder blade and check debris around the chopping blade area.

After cleaning the internals, put everything back as you found it, or replace worn out parts while at it.

b) Insufficient water spraying into the dishwasher

Another cause of weird grinding dishwasher noise is if insufficient water sprays into the machine.

Check the inlet valve for clogs or other issues that may be preventing water from entering the dishwasher.

Dishwasher making a continuous drone-like sound or even high-pitched sound

If your dishwasher is making loud droning noise during operations, then the likely cause is that the bearings on the circulation pump have gone bad.

c) Circulation pump issue

If the pump motor bearings are faulty, water pressure won’t be generated through the spray arms. Replacing the motor and pump should fix the problem and stop the continuous drone-like sound as well.

Wash pump motor bearings failed

Buzzing noise turning into sort of banging sound

Usually, when pushing dirty water down the drain, dishwashers make a buzzing noise.

Buzzing noise is also normal in the wash cycle as the soft food disposal unit grinding down food particles.

But if the buzzing start tuning into kind of a banging sound then the following could be the cause:

a) Spray arms may be hitting the dishes

If the banging sound has a certain rhythm to it, then probably the spray arms are banging on the dishes.

The reason for rhythmic banging is because spray arms usually rotate in a circle. Fix this banging dishwasher noise by readjusting the dishes.

But if the banging inside the dishwasher is non-rhythmic, you might want to call a plumber because you most likely are experiencing water hammer.

b) Water pipeline hammer knock sound

Water hammer issue happens due to sudden valve shutting leading to rapid bursts of water to rattle pipes such that they bang against the surrounding.

Use a water hammer arrestor to take care of water hammer issue.

Dishwasher making knocking or banging noise

If a recently installed dishwasher is making thumping noises, then you probably installed it too close to the cabinet, and the drain line is vibrating against the walls of the cabinet.

Adjusting the dishwasher’s location should fix the issue.

Dishwasher making humming noise

The hum of the dishwasher pump during the wash cycle is normal. But if the humming gets too loud, then the following could be the cause:

a) Ventilation Fan

Is your Whirlpool dishwasher making a loud humming noise, especially during the drying cycle?

Then the most likely culprit is the drying fan. Fixing the fan should reduce the humming volume.

b) Wash Pump Faulty motor

if the dishwasher is making high-pitched noise, i.e., a high-pitched hum, then you probably have a defective motor.

The good news is you don’t need to replace the dishwasher, just get your mitts on a new suitable motor and switch out the old one for the new.

Always ensure to cut off the power supply before starting to work on your dishwasher—Observe electric safety rules.

Dishwasher making noise when draining

So, your beloved quiet dishwasher machine goes through the wash cycle well, but when it comes to draining, it makes loud grinding, rubbing, or humming sound?

The likely cause of noise during draining could be:

a) Seized drain pump issue

The drain pump helps to drain water out of the dishwasher machine.

If something is lodged inside the sump unit or the drain pump is faulty, the dishwasher will make weird sounds during the drain cycle.

Check for debris around and inside the drain pump, and even if after cleaning the unit, the noise continues, replace the dishwasher’s drain pump.

Dishwasher making a strange rattling noise

When a dishwasher is running, rattling sounds are normal due to loose forks or dishes touching each other as they are jostled by water.

Rattling or squealing is also normal if there’s no water in brand new dishwashers or if you have not used it in a long time.

Adding some water to the tub should fix the issue. But if rattling becomes excessive, then the cause could be:

a) Faulty Wash motor

Run an empty wash cycle to inspect the motor. If rattling happens, the cause is a faulty motor since there’ll be nothing inside the dishwasher except the motor.

Other causes of weird rattling noises include blocked filter, clogged drain, etc. check for foreign items around the issue.

The take-home?

The hiss of water as it rushes through the inlet fill valve or the gentle hum of the motor pump are normal dishwasher sounds.

Dishwashers have components, so it’s normal for them to make some noise during operations.

But if the noise gets strange and loud, it could be an indication of technical failures such as seized drain pump, clogged filter, faulty fan, and motor, etc. move quickly to resolve, or you are going to pay more to fix the issues if they go unchecked for too long.

Why is the dishwasher making noise?

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