Why Bosch Dishwasher Is Making Clunking Noises? Reasons and Fixes

It’s quite common to hear some clunking and buzzing noises from your Bosch dishwasher. The reasons behind these noises could be multiple. This guide will provide you with the most common causes and their solutions for clunking noises coming out of Bosch dishwashers.

Solutions for Bosch Dishwasher that’s Making Clunking Noises

1. Circulation Pump

The bearings present on the circulation pump motor wear out over time. Especially if your dishwasher is old, then bearings must be damaged. Due to wear-out bearings, you will hear an awkward sound from the circulation pump when the dishwasher is in use.

If the bearings on your circulation pump are damaged, you will have to replace the entire circulation pump. You must call a professional to replace the circulation pump because it will be risky if you replace it by yourself.

2. Drain Impeller

The drain impeller works to push water into the drain hose and garbage disposal. It is one of the main parts of the drain pump. Any fault in the drain impeller will cause different noises from the dishwasher. If the drain impeller is broken, you should replace it.

You can access the drain impeller from the bottom of the dishwasher. Moreover, you can reach the drain impeller after accessing the drain pump. If the drain impeller is faulty, you will have to replace it. After replacing the drain impeller, turn on the dishwasher. If you still hear strange noises, there could be another reason behind it.

3. Drain Pump Motor

A clogged or damaged drain pump also causes clunking noises to come out of your Bosch dishwasher. The drain pump provides power to the drain hose to drain out dirty water from the dishwasher. It is present near the bottom access panel and toe panel. If it is cloggy or faulty, it will cause various noises.

First, check the drain pump for any blockage. Remove the bottom access panel and toe panel to reach the drain pump. Now remove the pump, and if you find it accumulated with debris and food particles, clean it. Use a clean damp cloth and scrub brush for debris removal.

After cleaning, reassemble the drain pump motor and check for the noises. If those clunking noises are still coming, then it means the drain pump motor needs to be replaced.

Click here to see how you can test drain pump on your Bosch dishwasher.

Drain pump motor

4. Wash Impeller

Wash impeller push water to the spray arms. One or more small plastic wash impeller blades are present in the dishwasher. If these wash impellers are broken or damaged, strange noises will come out of your Bosch dishwasher. Wash impellers could be bent or warped against the pump housing.

You have to scrutinize the wash impellers. You can access the wash impellers from inside the dishwasher’s tub. If you find them broken, you will have to replace them. You can replace them without changing the pump and motor assembly.

You should check your dishwasher’s model. If your wash impellers are replaceable separately, then it’s good. If you cannot replace wash impellers individually according to your model, you have to replace the entire motor and pump assembly.

5. Water inlet valve

The water inlet valve allows the water to enter the dishwasher. New water inlets valves are very quiet in operations and do not produce any sounds. With time, the diaphragm present inside the valve deforms and deteriorates. This deformed diaphragm interacts with water coming inside and makes clunking and buzzing sounds.

Important Information

With a Master Protection Agreement, your appliance is covered 100% if your appliance has any issues due to defects in manufacture or normal wear and tear for up to 5 years (renewable). You will also have up to 3 years of cosmetic defect protection. Read more about it here.

To ensure either water inlet valve is behind these noises, you must check it carefully. During the filling cycle, hear the noises coming out of the dishwasher. If you hear loud noises during the filling cycle, it means it’s due to a faulty water inlet valve.

water inlet valve

Thus, it would help if you replace the water inlet valve to dismiss all the sounds coming from your Bosch dishwasher. You should take professional help in changing the water inlet valve for perfection.

Frequently Asked Questions

1. Why is my Bosch dishwasher making rattling and knocking sounds?

Due to incorrect loading, the spray arm of the Bosch dishwasher may hit the utensils and produce a rattling and knocking sound. To resolve this issue, you have to rearrange the dishes within the dishwasher making noise. You have to provide the entire space to spray arms for rotation without any obstacles.

3. What is the reason for noises coming out of the dishwasher when turned off?

When you turn off your dishwasher, the compartments inside the door snap to release the dishwashing detergent. After the rinsing cycle, the fans present in the door spin to let the steam out. As a result, you will hear humming and grinding sounds that are quite common, and nothing to worry about.

3. Why does the Bosch dishwasher become suddenly noisy?

When the Bosch dishwasher forces water into the drain, it produces grinding and buzzing noises. These noises are expected during the draining process and rinsing. But if you hear a loud sound from your dishwasher, you should check your pump impeller.


  • Stephen Powers

    Appliance repair guy from Washington. I am majorly experienced in dishwashers, water filters and refrigerators, AMA on my twitter account.

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