My Bosch Dishwasher Makes a Loud Knocking Sound

Normal Noise

• Although models vary in features and operations, all Bosch dishwashers make some sort of noise during the course of their cycles. Normal noises include water running and chopping or pulsating during the drain cycle. The motor of the unit may also start and stop during the cycle. For a full list of normal noises, check the use and care manual of for your specific model of Bosch dishwasher.

Loud Knocking Sounds

• Regardless of the model of your Bosch dishwasher, loud knocking sounds aren’t normal. It usually indicates that either the dishes are knocking against each other or the sprayer arms are hitting something. If you hear knocking, open the dishwasher to verify that the arms are rotating freely. Check your dishes for breaks or chips, which indicate they’re hitting each other.

Best Loading Practices

• To avoid a loud knocking sound, try loading your dishes according to the best practices in your Bosch dishwasher manual. Position the dishes so that they don’t touch or overlap each other. Put your heavier cookware on the bottom rack and leave the lighter items, like cups, on top. Place your flatware inside the basket or special flatware rack that some units come with to avoid them flying around during the cycle. Also, check that sprayer arms can rotate freely before you start each cycle.

Overloading

• Avoid overloading your Bosch dishwasher in all situations. If you can’t place your dishes in the racks without letting them touch each other, you’re trying to wash too many dishes at once. Break it up into smaller loads, washing similarly shaped and weighted items together. For extra large items, such as pots, remove the top rack and wash one or two at time. It may take more water, electricity and time but it will prevent damage and unnecessary noise.