dishwasher

Dishwasher Making grinding or loud noise during cycle

A grinding or loud noise during a dishwasher cycle is usually caused by a worn or damaged wash pump, a faulty motor, or debris caught in the chopper blade or spray arm. This guide will walk you through diagnosing the source of the noise and replacing or clearing the affected components. With basic hand tools and careful attention to safety, most homeowners can complete this repair in one to two hours.

1. 1

   Disconnect Power and Water Supply

   Before touching any internal components, unplug the dishwasher from its electrical outlet or turn off the dedicated circuit breaker in your home's electrical panel. Locate the water supply valve under your kitchen sink and turn it clockwise until it stops to shut off the water. This step is non-negotiable and must be completed before any other work begins.

   warning

   Never work on a dishwasher that is plugged in or connected to live power. Electric shock can be fatal.

   tip

   Take a photo of the area under the sink and behind the dishwasher before you start — it helps when reassembling connections later.

2. 2

   Identify the Source of the Noise

   Run the dishwasher briefly while it is still safe to observe — listen carefully to determine when in the cycle the noise occurs. A grinding noise during the wash cycle often points to the wash pump or chopper blade. A loud humming or rattling during draining usually indicates the drain pump. A clunking or banging noise may mean a spray arm is hitting dishes or is cracked. Use this observation to focus your inspection in the steps ahead.

   tip

   If the noise happens only when water is draining, focus your repair on the drain pump. If it happens throughout the wash cycle, start with the wash pump and chopper area.

   warning

   Do not reach inside the dishwasher while it is running. Observe only from a safe distance.

3. 3

   Remove the Lower Dish Rack and Spray Arm

   Pull out the lower dish rack completely and set it aside. Locate the lower spray arm at the bottom of the dishwasher tub. Most spray arms simply unscrew or unclip — turn it counterclockwise or press the release tab depending on your model. Lift it off and inspect it for cracks, broken nozzles, or any debris jammed in the holes. Rinse it under warm water and clear any clogged holes with a toothpick or thin wire.

   tip

   A cracked or warped spray arm can wobble and hit dishes or the tub wall, causing a loud clunking noise. If you see visible damage, replace the spray arm before going further.

   warning

   Spray arm edges can be sharp — handle with care to avoid cuts.

4. 4

   Clean and Inspect the Filter and Chopper Blade

   Remove the cylindrical filter assembly located at the bottom center of the dishwasher tub. Twist it counterclockwise and lift it out. Rinse the filter under running water and use a soft brush to remove grease and debris. Below the filter you will find the chopper blade — a small plastic or metal disc that breaks down food particles. Look for broken teeth, lodged debris like glass shards or bone fragments, or warping. Remove any foreign objects with needle-nose pliers. A damaged chopper blade must be replaced.

   warning

   Glass fragments and bone chips are extremely sharp. Wear rubber gloves when reaching into the filter area.

   tip

   A clogged or broken chopper blade is one of the most common causes of grinding noise and is an inexpensive fix.

   part

   Chopper blade — check your dishwasher's model number (usually on a sticker inside the door frame) to find the correct replacement part.

5. 5

   Access the Wash Pump and Motor Assembly

   To inspect the wash pump, you will need to access the underside of the dishwasher. Carefully pull the dishwasher forward out of its cabinet space — you may need to remove two mounting screws from the top of the door frame that anchor it to the countertop. Tilt the machine gently onto its back or side (place cardboard or an old blanket down first to protect the floor and the unit). Locate the pump and motor assembly on the underside — it is typically a round or oval plastic housing connected to the drain hose and water inlet.

   warning

   Dishwashers are heavy — typically 50 to 80 pounds. Ask a second person to help you tilt and move the unit safely to avoid back injury.

   warning

   Confirm power is still disconnected before proceeding. Double-check the circuit breaker.

   tip

   Take photos of every hose connection and wire harness before disconnecting anything. This makes reassembly much easier.

6. 6

   Inspect the Wash Pump Impeller

   Remove the pump cover by releasing the retaining clips or unscrewing the fasteners holding it in place. Inside, you will find the impeller — a spinning disc with fins that circulates water. Spin the impeller by hand. It should rotate smoothly with slight resistance. If it feels gritty, rough, or does not spin freely, the bearings are worn and the pump assembly needs to be replaced. Also check for debris like broken glass wrapped around the impeller shaft.

   tip

   A grinding noise that mimics the sound of gravel in a blender almost always means the pump impeller bearings have failed.

   part

   Wash pump assembly — use your model number to source the correct OEM or compatible replacement pump.

7. 7

   Inspect the Drain Pump

   The drain pump is a smaller unit usually located beside or below the main wash pump. Disconnect the wiring harness connector by pressing the release tab and pulling it apart — do not yank on the wires. Detach the drain hose clamp using pliers and slide the hose off. Unscrew or unclip the drain pump from the housing. Check the impeller inside for debris or damage. If the pump motor makes a grinding sound when it runs or the impeller is cracked, the drain pump should be replaced.

   tip

   Drain pumps are relatively inexpensive and easy to replace — if in doubt, replacing it is a cost-effective decision.

   warning

   Residual water may drain out when you disconnect the hose. Place a towel or shallow pan beneath the connection point.

8. 8

   Replace Damaged Components

   Install your replacement parts — whether that is the chopper blade, spray arm, wash pump, or drain pump — by reversing the removal steps. Secure all mounting screws and retaining clips firmly. Reconnect all wiring harness connectors until you hear or feel them click into place. Reattach hose clamps securely to prevent leaks. Make sure no wires are pinched between components. Double-check every connection before reassembling the outer unit.

   tip

   Refer to the photos you took during disassembly to confirm every connector and hose is returned to its original position.

   warning

   Loose hose connections will cause water to leak under your floor — tighten all clamps until snug but do not overtighten and crack the plastic fittings.

9. 9

   Reassemble and Return the Dishwasher to Position

   Once all components are secured, carefully stand the dishwasher upright and slide it back into the cabinet opening. Reattach the mounting screws to the underside of the countertop. Reconnect the water supply line and tighten the fitting firmly by hand, then a quarter turn more with a wrench. Plug the power cord back in or re-enable the circuit breaker.

   tip

   Leave the dishwasher door open slightly until you have run a test cycle — this makes it easy to pull it back out quickly if a leak appears.

10. 10

    Run a Test Cycle and Check for Noise or Leaks

    Turn the water supply back on and watch under the sink for any drips at the supply line connection. Run the dishwasher on a short or rinse-only cycle. Stand nearby and listen carefully through the entire cycle — wash phase, rinse phase, and drain phase. The grinding or loud noise should be gone. Also check the floor around and under the dishwasher for any water after the cycle completes. If the noise persists, recheck the pump impeller and spray arm for any remaining debris or damage.

    tip

    Running a cycle without any dishes inside makes it easier to hear subtle noises and spot any leaks early.

    warning

    If you smell burning, see smoke, or hear electrical buzzing at any point, immediately turn off the circuit breaker and do not use the appliance until a professional has inspected it.