Bosch Dishwasher: unusual noise during operation

Professional Repair Guide

What is this symptom?

Experiencing unusual noise from your Bosch dishwasher during wash or drain cycles? Sounds like grinding, buzzing, or knocking can indicate issues like improper loading or debris in the pump. Address these to restore quiet operation.

Urgency: Medium

Important Tips for Bosch Models

  • Bosch’s official guidance highlights that spray arms hitting utensils due to improper loading is a common cause of noise.

Possible Causes

Spray arms hitting dishes or utensils due to improper loading

How to Identify: Rattling or knocking sounds occurring during wash, especially if dishes are loosely placed or obstructing spray arm rotation

Part: Spray arms/loaded items

Debris or foreign objects in drain pump or filter area

How to Identify: Grinding or loud buzzing during drain cycle; standing water or slow draining may accompany

Part: Filter, drain pump impeller

Clogged spray arms or filters affecting water flow

How to Identify: Noise accompanied by uneven water spray performance, possibly less effective cleaning

Part: Spray arms, filters

Drain hose blockage or pump obstruction

How to Identify: Gurgling and humming during drain; hoses may be kinked or obstructed

Part: Drain hose, drain pump

Worn motor bearings or internal pump issues

How to Identify: Persistent grinding or whining not resolved by cleaning or realigning loads

Part: Motor bearings, circulation pump

DIY Solutions

Correct Loading to Prevent Spray Arm Contact

Easy 5-10 minutes
  1. Pause the dishwasher and open the door once safe
  2. Rearrange dishes ensuring spray arms can rotate freely and items do not touch each other
⚠️ Safety First: Ensure dishwasher cycle is stopped before adjusting load

Clean Filters and Check for Debris

Moderate 10-20 minutes
Tools Needed: Gloves, Warm water
  1. Turn off power to the dishwasher
  2. Remove lower rack and locate filter assembly
  3. Take out and rinse filters to clear trapped debris
  4. Reassemble filters and rack
⚠️ Safety First: Disconnect power and avoid sharp debris

Inspect and Clear Spray Arms

Moderate 10-15 minutes
Tools Needed: Warm soapy water, Small brush
  1. Turn off power and remove spray arms
  2. Inspect holes for mineral buildup or blockages
  3. Clean spray arms with brush and reattach
⚠️ Safety First: Handle arms carefully

Check Drain Hose and Hose Routing

Moderate 10-15 minutes
Tools Needed: Flashlight
  1. Turn off dishwasher and water supply
  2. Access and inspect the drain hose for kinks or obvious clogs
  3. Straighten hose and clear any visible obstruction
  4. Reconnect hose and run a short cycle to test
⚠️ Safety First: Turn off power and water

Professional Repairs

Pump or Motor Assembly Repair/Replacement

Estimated Cost: $150 - $400

Professional Inspection of Internal Components

Estimated Cost: Diagnostic fee $80-$150 plus parts

When to Call a Professional

Noise persists after cleaning filter and removing blockages
Grinding or whining indicating possible internal component wear
Unusual noises accompanied by performance issues (poor cleaning, drainage issues)

Preventive Maintenance

  • Clean filters and spray arms: Noise from blockages and improves water flow
    Frequency: monthly
  • Check loading practices: Spray arm obstructions causing knocking/rattling
    Frequency: Every use

Frequently Asked Questions

Why is my Bosch Dishwasher unusual noise during operation?
Common causes include spray arms hitting dishes, debris in the drain pump, or clogged spray arms.
How do I fix Bosch Dishwasher unusual noise during operation myself?
Try correcting the loading of dishes, cleaning filters, and inspecting spray arms for blockages.
How much does it cost to fix unusual noise during operation?
Professional repairs can range from $150 to $400, depending on the issue.
When should I call a technician for unusual noise during operation?
If the noise persists after DIY fixes or if you suspect motor or pump issues, it's time to call a professional.

References & Sources

Community Analytical Insights

Analysis based on real user discussions from appliance repair communities

Can I Fix This Myself?

75%
DIY Success Rate Difficulty: Either

Common Issues Reported by Users

  • Diverter valve malfunction causing water to flow improperly
  • Foreign objects lodged in the spray arms or filter
  • Worn or damaged motor bearings leading to unusual sounds

User Suggested Solutions

  1. Inspect and clean the diverter valve. Remove the lower spray arm and check for blockages. If the valve is faulty, replace it.

  2. Check the spray arms for obstructions. Remove any debris and ensure they can spin freely.

  3. Inspect the motor bearings for wear. If damaged, replace the motor assembly.

Analysis based on 1 community discussions
View Sources

Data compiled from real discussions on r/appliancerepair and r/Appliances:

  1. Figure out the sound! Bosch 500 Series Dishwasher - Replaced...

Community Discussions

consistent 'wooshing' perhaps 'humming' sound during rinse cycles

The issue was identified as the diverter.

DIY View on Reddit →

Source: Reddit r/appliancerepair

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