Why is Your Dishwasher Making Grinding Noises?
May 26, 2021

Why is Your Dishwasher Making Grinding Noises?

Why is Your Dishwasher Making Grinding Noises? 



Here at Fossil Blu we have worked next to many a home dishwasher. While your sink may be new and beautiful, that dishwasher may have seen better days. Today, we're here to show how your dishwasher can be fixed so it's as elegant (and quiet) as the rest of your kitchen design.

Dishwashers are rarely silent machines. Engineers do what they can to make whisper-quiet wash cycles and sound-insulate the cabinet, but a machine is a machine.  Your dishwasher needs to spray water around at some very high speeds in order to fully wash your dishes, and that makes noise. Your dishwasher also uses internal machinery to switch from phase to phase of the washing cycle. Long story short, there will be some noises.

Every dishwasher makes sounds. But there's a certain kind of sounds where your ear knows that something is wrong. Grinding sounds immediately cause us to worry about parts breaking, electricals frying, and future repairs to be done. Our ears also perk up at certain drain sounds we associate with clogs and partial clogs. So this article will help you identify the sounds you're hearing, whether they're a problem, and if so how to enact a solution.


Clicks and Revving - Normal

The first thing to know is what's normal for your dishwasher. Most dishwashers make a certain amount of clicking, revving, and swishing sounds. Dishwashers with a manual timer dial often clack, ratchet, and even clunk from mode to mode. These sounds can even be quite loud. However, there's a difference between typical dishwasher noises and noises that indicate a problem.

The best thing you can do is grow accustomed to the normal sounds of your dishwasher. Then take note when or if those sounds change. If the sounds become louder, more irregular, or  gain a rough quality to the sound, it's time to investigate and think about repairs.


Built-In Garbage Disposal - Working Properly or Something Stuck

The first possible option is that something is obscuring your dishwasher garbage disposal. Many dishwashers have a set of dedicated blades just below the drain, similar to the garbage disposal in your sink. This functions to chop up any large food debris and make it easier to pull down the drain, allowing the dishes to become clean.

However, not everything that makes it into the dishwasher can be ground up. The occasional lost piece of silverware or cooking utensil can sometimes make it in. Chopsticks are a particularly notorious problem, as they can slip through dishwasher basket compartments and down into the drain at the bottom of the tub.

Sometimes, the grinding sound is your garbage disposal working properly, a brief spin to break up food items. But if you hear that distinctive scrape and rattle, you may need to open up the drain and remove the obstructing item.


Failing Cycle Timer

The cycle timer is what determines the dishwasher's phase, from washing to rinsing to drying. Often, a slow clacking or ratchet sound is the cycle timer spinning to the next phase. It does this with a sequence of gears and electrical signals. If those gears malfunction, the teeth can stop connecting and the dishwasher may stop reliably shifting between wash phases. The failure of these gears can make a signature grinding sound, much louder and more alarming than the usual clack of the dishwasher going through its cycle.

The cycle timer is usually located inside the dishwasher door. You or a technician will need to take the door apart to reach and replace the mechanism assembly. Start by removing the front panel and opening the control panel.


Clogged Drainpipe

Another common sound from your dishwasher is a clogged drain pipe. The drain line, hose, or pipe carries away all the food bits and washed away particles so that the food can become clean. When soapy and rinse water are done, they are drained away as well. Most people know that drains can make some serious noise and your dishwasher drain is no exception.

A partially clogged drainpipe can make a riot of hollow gurgling sounds, along with the spooky sound of suddenly draining hours after the dishwasher has run. Drain care is essential for keeping your dishwasher and its drain quiet. Run the garbage disposal and flush the drain with hot water down the kitchen sink. If necessary, clear the dishwasher drain and then run a snake through your drain line to find the partial clog.

With the clog removed or neutralized, your dishwasher drain should be quiet again.


Obstructed Dishwasher Impeller

The dishwasher impeller helps to increase the water pressure of water about to spray out of the spinning arms and any additional nozzles. The impeller is a spinning piece and, therefore, is capable of making a grinding sound if obstructed. Dishwasher impellers are a built-in part of the drain system, the part that cycles water to be reused again. If a small food piece, plastic, or utensil is wedged in your dishwasher impeller, it may need to be removed before the impeller returns to silent work.


Failing Pump Motor

Lastly, let's talk about the pump motor. The dishwasher has one or two pumps, often one unified drain pump that helps to both wash the dishes and clear the drain. When a motor starts to fail, the noise it creates can crescendo. What was once a low pleasant hum telling you the dishwasher is running becomes a deafening roar or a not-so-pleasant grinding sound from about underneath the dishwasher.

If this sounds familiar, and especially if there is still water in the bottom of the tub, consider the pump motor. A dishwasher repair technician can open up your dishwasher to test and potentially replace your pump motor.  If the pump motor was a problem, repair or replacement should significantly reduce the sound of your dishwasher.


An intrusively loud dishwasher is almost always a sign of trouble. While no dishwasher is silent, most try to be. The noisier your dishwasher gets, the  more urgent the repair must be. You can count on us to take care of all your dishwasher maintenance needs, including hunting down the source of a grinding noise that echoes through the house each time dishes are run.

As experts on sinks, we've worked near and with a lot of dishwashers. While we are not professional appliance repair technicians, we can help you solve problems related to sink position, design, and professionally installed plumbing with your dishwasher as part of your new improved kitchen design. Contact us today to talk about kitchen renovation and improvements!