Pressure Washer Making a Knocking Noise

Quick answer

A knocking noise in your pressure washer is often caused by loose parts, a clogged pump, or a damaged connecting rod. Turn off the unit, check for loose components, clear any clogs, and inspect the pump for damage. If the noise persists, consider professional repair.

Confirm the symptom

• Hearing a rhythmic knocking or tapping sound while the pressure washer is running
• The noise increases with engine speed
• The pressure washer vibrates more than usual

Tools and prep

• Pressure washer owner’s manual
• Adjustable wrench or socket set
• Screwdrivers (flathead and Phillips)
• Clean cloth or rag
• Replacement parts if needed
• Work gloves
• Safety glasses

Step-by-step troubleshooting

1. Turn Off and Unplug the Pressure Washer
   Do: Shut off the pressure washer and disconnect it from the power source or fuel supply.
   Observe: The unit is completely powered down and safe to handle.
   Means: Prevents accidental startup and electrical shock.
   Next: Drain the system
2. Drain the System
   Do: Open the pressure release valve and drain any remaining water from the pump and hoses.
   Observe: Water drains completely from the system.
   Means: Reduces pressure and prevents leaks during inspection.
   Next: Inspect for loose parts
3. Inspect for Loose Parts
   Do: Check all bolts, nuts, and connections on the pump, engine, and nozzle for tightness.
   Observe: Any loose or missing components are identified.
   Means: Loose parts can cause knocking noises and should be tightened or replaced.
   Next: Check for clogs
4. Check for Clogs
   Do: Inspect the nozzle, hose, and pump inlet for blockages. Use a clean cloth or small brush to clear any debris.
   Observe: Debris or buildup is removed from the system.
   Means: Clogs can restrict water flow and cause unusual noises.
   Next: Test the pump
5. Test the Pump
   Do: Visually inspect the pump for cracks, corrosion, or worn-out seals. Check the connecting rod for damage.
   Observe: Signs of wear or damage are noted.
   Means: A damaged pump or connecting rod can cause knocking sounds.
   Next: Replace faulty parts
6. Replace Faulty Parts
   Do: Replace any damaged or worn-out parts, such as the connecting rod, seals, or pump.
   Observe: The knocking noise is eliminated after replacement.
   Means: Faulty components are the source of the noise.
   Next: Reassemble and test

Common causes

Parts matching

Common parts that may be needed to fix a knocking noise in your pressure washer include:

• Bolts and nuts for securing components
• Nozzle and hose for clearing clogs
• Connecting rod for replacing if damaged
• Pump seals to prevent leaks
• Pump oil for lubrication
• Unloader valve for pressure regulation

Refer to your pressure washer’s owner’s manual for the correct part specifications and compatibility.

When to call a professional

• The knocking noise persists after replacing all loose parts and clearing clogs
• You notice visible cracks or severe damage to the pump or engine
• The pressure washer does not operate properly after repairs
• You are unsure about disassembling the pump or engine components
• The noise is accompanied by a burning smell or smoke

FAQ

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