Repairing a Strange Noise in a Maytag MDBC5550 Dishwasher

Repairing a Strange Noise in a Maytag MDBC5550 Dishwasher

Introduction

A dishwasher that starts to make unfamiliar sounds can be unsettling. Whether it’s a rumbling thud, a whirring hiss, or a sharp clanging, a strange noise usually indicates that something inside the unit is out of balance or failing. The Maytag MDBC5550, known for its reliability, can still develop minor mechanical problems that can be diagnosed and fixed with a bit of patience and the right tools. This guide walks you through a systematic approach to identify the source of the noise and repair it, keeping your appliance running smoothly for years.

Safety First

Before any work begins, disconnect the dishwasher from the power supply. The MDBC5550 draws significant current, and working on an energized unit can cause electric shock. Unplug the appliance from the outlet or, if you prefer extra caution, switch off the circuit breaker that powers the dishwasher. Ensure the water supply valve is closed to avoid accidental water spillage.

Common Causes of Strange Noises

1. Worn or Bent Spray Arms – The rotating arms can become damaged by hard water deposits or foreign objects, leading to vibrations.
2. Faulty Drain Pump – A clogged or damaged pump impeller can create a grinding or rattling sound during draining.
3. Motor Issues – An aging motor may develop loose bearings or worn brushes, producing a humming or ticking noise.
4. Air in the Drain Hose – If the hose is not properly seated, trapped air can cause a splashing or clunking noise.
5. Door Latch or Gasket Problems – A loose latch or worn gasket can make a clicking or rattling sound as the door cycles.
6. Electrical Components – Faulty control board relays or capacitors can emit buzzing or humming.

Understanding these possibilities helps narrow the investigation and target the most likely culprit.

Tools and Parts You’ll Need

• Adjustable wrench
• Phillips and flat‑head screwdrivers
• Allen key set
• Multimeter (for electrical checks)
• Replacement spray arm (if needed)
• New drain pump impeller or unit (if needed)
• New motor bearings or brushes (if needed)
• Replacement door latch or gasket (if needed)
• Cleaning brush or small file
• Rags and a bucket for water

Having these tools ready saves time and keeps the repair process orderly.

Diagnostic Approach

The goal is to listen, isolate, and test. Begin by observing when the noise occurs—during wash, rinse, or drain. This timing clues you into whether the issue lies with the pump, spray arms, or motor.

Step 1 – Inspect the Spray Arm

• Open the dishwasher and remove the lower rack to access the spray arm.
• Detach the arm by loosening the retaining clip or bolt.
• Rotate the arm manually. A smooth rotation indicates a good impeller; wobbling or resistance suggests damage.
• Look for bent or missing pins. A bent arm will cause uneven water flow and vibration.
• Clean the arm with a soft brush to remove mineral buildup.

If the arm is bent or clogged, replace it with a new one from a reputable source. Install it by reversing the removal steps.

Step 2 – Check the Drain Pump

• Locate the drain pump at the bottom rear of the dishwasher.
• Disconnect the pump’s electrical connector and remove the hose clamps.
• Inspect the impeller for debris or wear. A broken impeller will not spin properly and will generate noise.
• Rotate the impeller by hand. It should turn freely. A grinding sound indicates a jammed or damaged impeller.
• If debris is present, clean it out. If the impeller is damaged, replace the pump housing or impeller.

After cleaning or replacing, re‑attach the hose clamps and reconnect the electrical connector.

Step 3 – Examine the Motor

• With the unit still unplugged, open the dishwasher’s access panel behind the kick plate.
• Locate the motor housing. Look for visible signs of wear: cracked plastic, discolored wiring, or loose screws.
• Use a multimeter to test the motor’s resistance. A reading outside manufacturer specifications suggests a bad motor.
• Check the motor brushes for wear. If they have worn down to less than 1.5 mm, replace them.
• Tighten any loose screws that secure the motor. Loose mounts can cause vibration and noise.

If the motor shows severe electrical faults, consider replacement rather than repair.

Step 4 – Test the Drain Hose

• Verify that the drain hose is seated firmly at the dishwasher’s drain outlet and at the sink or garbage disposal.
• Check for kinks or bends that could restrict flow.
• Remove the hose clamp, inspect the hose for blockages or cracks, and clean or replace as needed.
• Reattach the hose clamp and ensure the hose is flush against the mounting point to prevent air intake.

A properly seated hose eliminates splashing or clunking sounds during draining.

Step 5 – Inspect the Door Latch and Gasket

• Open the dishwasher door and examine the latch mechanism. A loose latch can click as it engages and disengages.
• Test the gasket for cracks, warping, or excessive wear. A damaged gasket can cause rattling noises when the door cycles.
• Tighten any loose latch screws and replace worn gasket material.

Step 6 – Check the Control Board

• Access the control board by removing the top panel inside the dishwasher.
• Inspect for burn marks, moisture damage, or loose components.
• Use a multimeter to test relay contacts and capacitor continuity.
• If any electrical component fails a test, replace it with a compatible part.

Reassembly and Testing

Once all components have been inspected or replaced:

1. Reinstall the spray arm, ensuring it locks securely.
2. Re‑attach the drain pump and hose.
3. Secure the motor and control board panels.
4. Replace the bottom rack and the top kick plate.
5. Reconnect the power and water supply.

Run a short cycle with no dishes inside to verify that the noise has been eliminated. Observe the dishwasher during each phase—wash, rinse, and drain—to ensure no new sounds appear.

If the problem persists, re‑check the areas most likely to have been missed: the pump impeller, motor bearings, or air trapped in the drain hose.

When to Call a Professional

• If you discover a major electrical fault that requires extensive rewiring or a new control board.
• When the dishwasher’s motor must be replaced and you lack the tools or experience for a motor swap.
• If the unit’s warranty is still active and you prefer manufacturer repair.

Professional technicians have specialized diagnostic equipment and access to OEM parts that can save time and guarantee a proper fix.

Maintenance Tips to Prevent Future Noise

• Regularly clean the spray arms with a small brush to remove mineral deposits.
• Check the drain filter every month and clean it to prevent clogs.
• Inspect the pump impeller annually for debris or wear.
• Use a dishwasher cleaner monthly to dissolve hard‑water buildup.
• Keep the door gasket lubricated with a silicone spray to prevent cracking.
• Run a rinse cycle after each wash to flush residual particles from the drain hose.

Adhering to these habits reduces the likelihood of noise and extends the appliance’s lifespan.

Conclusion

A strange noise in a Maytag MDBC5550 is often a sign of a component that has worn or become misaligned. By following a systematic diagnostic routine—checking the spray arm, drain pump, motor, hose, latch, and control board—you can usually pinpoint the issue and resolve it with straightforward repairs. Remember to prioritize safety, use the right tools, and perform regular maintenance to keep your dishwasher humming smoothly. With a bit of diligence, your appliance can continue delivering spotless dishes for years to come.