What Causes Pressure Washer Pumps To Fail?

Pressure washer pumps are the heart of any pressure washing system. When taken care of properly, they can last a lifetime. However, like any complex machinery with moving parts, they can fail if not maintained.

Think you know pumps? If you want yours running smoothly, make sure you understand these basic maintenance tips.

What Are the Most Frequent Causes of Pressure Washer Pump Failures?

Pressure washer pumps often fail due to poor maintenance. The following are the main causes for pump failure in our experience:

• Low oil
• Deteriorated or contaminated oil
• Insufficient water flow from source
• Unaddressed leaks
• Clogged inlet filter, or missing/damaged filter
• Worn seals

To prolong the life of your pump and avoid costly repairs, adhere to the maintenance schedule outlined in your manual, and inspect components regularly.

It's easy to damage your pump if you're not sure how to operate it correctly. Using contaminated water, overheating by running it in bypass mode for too long, or using the wrong chemicals can all reduce your pump's lifespan.

How Should I Inspect My Pressure Washer Pump?

Regularly checking and replacing worn parts can keep small issues from turning into big problems. Follow your manual for a complete checklist, but remember, maintaining your pump's longevity means inspecting more than just the pump itself.

• Monitor Your Oil. Check the oil level, and make sure it's clean.
• Look For Leaks. Since valves and seals are subject to wear and tear over time, keep an eye out for any oil or water leaks. One good way to catch a water leak is to use a pressure gauge to monitor for pressure loss- which would be a sign of a bad seal.
• Inspect Your Filter Screen: Make sure to regularly inspect the filter screen on the inlet of the pump. If this screen is dirty, damaged, or missing, it should be cleaned or replaced. This filter protects your pump from particles that can speed up seal wear. However, a clogged filter can restrict water flow, leading to an insufficient water flow which can damage your pump.
• Replace Worn Nozzles and Hoses: Keep in mind that worn or clogged nozzles and hoses can restrict water flow. In a properly operating machine, this shouldn't cause significant pump overheating since the unloader should open and bypass some of the water, but it will affect your pump’s efficiency. To not stress your pump, inspect and replace these components to ensure optimal performance.

What Should I Look For When Inspecting My Oil?

Like any machine with moving parts, lubrication is key to longevity. Since one of the most common reasons for pump failure is poor oil quality, it is important to know what to look for when inspecting the oil in your pump.

• Check the Oil Level: Most pressure washer pumps have a sight gauge and dipstick to help monitor the oil level. It is best to use both to get the most accurate reading, but if machine components are blocking your view of the sight glass, you may only be able to use the dipstick.
  The dipstick gives you a better view of the oil’s condition and allows you to check for any burnt smell.
  On a level surface, the oil should always be at least half full. If it's lower, top it off immediately to prevent the pump from running dry. Make it a habit to check your oil regularly!
• Pay Attention to Leaks: Regularly inspect your pump for any signs of oil leakage. Even a small leak can lead to a significant drop in oil levels, which can quickly damage your pump.
• Look for Contaminated or Milky Oil: While your pump’s oil will naturally darken over time, any sediment, metal particles, or a milky appearance means there's a problem. A milky look indicates that water has mixed with the oil, usually due to a seal issue, which can lead to increased wear, overheating, and pump failure.
  Water can also mix with the oil if your pressure washer is positioned too close to your cleaning area. The vented oil cap can allow water from overspray to enter the pump, so keep the machine at a distance to prevent this. Using your pressure washer to clean itself is a bad idea for this reason.

How Often Should I Change My Pump’s Oil?

Just like a car, your pump needs regular oil changes to keep its internal components well-lubricated. Without proper lubrication, piston rings, bearings, and seals can wear out, leading to pump failure if not addressed. 

How often you need to change the oil depends on your pump type, so check your pump's manual for the recommended intervals. Make sure to use the correct weight oil - improper oil can accelerate friction, overheating, and eventually pump failure. If you're unsure when the oil was last changed, inspect it through the sight gauge. When in doubt, it's best to change it with fresh oil.

How Do I Take Care Of The Brass Side of My Pump?

The water side of a pressure washer pump, also referred to as the brass side, is also prone to its own set of failures. Ensuring that the water flowing through your pump is clean and free of contaminants is crucial to preventing damage.

• Make Sure Your Water Supply Can Keep Up: Your water supply should exceed the pump's demand by at least 10%. For example, a 4 GPM pump requires a water flow of least 4.4 GPM. The best way to verify this is by performing a bucket test on the water hose feeding the machine, which will also determine if the hose size is sufficient.
  
  After confirming adequate flow, check for leaks to ensure all the water is reaching your pump. Fix any leaks immediately, whether they're at the spigot, filters, hose connections, or under the pump. Ignoring them can cause cavitation, which can seriously damage the pump.
• Never Run Your Pump Dry: This should be a given, but running your pressure washer pump without water will quickly overheat your system, damage the seals, and permanently impact the pressure your machine will output.
• Feed Your Pressure Washer Clean Water: Always use clean, filtered water for your pump. Sediment and debris can damage brass parts and lead to costly repairs, so it is important to check that the small screen on the pump’s intake is in good condition to keep out dirt.

  If it is damaged, missing, or excessively dirty, it should be replaced.

  If you are sourcing water from a lake or basin that may contain sediment, you need to add an inline filter to protect the pump.

• Only Run Safe Chemicals Through Your Machine: Not all chemicals are safe to run through your pressure washer pump. High-pressure detergents, for example, can damage seals and check valves if they are not designed to be used with your specific pump. Always check your pump’s manual to see which chemicals are safe to use.

How Should I Store My Pressure Washer?

Proper storage is critical for the longevity of your pressure washer pump, especially during the winter season.

• Store in a Dry, Cool Place: When not in use, store your pressure washer in a dry, cool place to avoid moisture buildup, which can lead to rust and corrosion.
• Winterize Your Pump: If you live in an area where temperatures drop below freezing, it's essential to winterize your pressure washer. Freezing water inside the pump can cause the components to crack and fail. This can be prevented by draining all water from the pump and adding antifreeze. While it is best to use Antifreeze specifically designed for pressure washers, RV antifreeze is a viable alternative, but it is best to consult your manual or contact one of our dealer experts for assistance.

Can The Wrong Attachment Damage My Pressure Washer Pump?

Yes. Using the wrong attachment can damage your pump, so it's crucial to ensure that your accessories match your machine's GPM and PSI specifications. Choosing the correct attachments helps prevent unnecessary stress on the pump and maintains optimal performance.

• Match the Nozzle to Your Machine: If the orifice size of your pressure washer nozzle is too small, the increased resistance can harm your pump. If you haven’t done so already, use a nozzle calculator to find the correct size for your machine. If your nozzle is incorrectly sized, replacing it is crucial to prevent damage and ensure optimal cleaning performance.

• Use a Pressure Gauge: Installing a pressure gauge can help you catch when any issue arises that causes a change in consistent pressure, reducing the risk of damage from over-pressurization or under-pressurization due to leaks or worn internals. A Gauge can be installed at the pump head, the outlet of the machine, and even at the trigger gun.

Can I Run My Pressure Washer Pump Continuously Without Overheating?

Overworking your pump can lead to premature failure, but not all pressure washers are created equal. Industrial machines are built to run all day long, but best practices still apply to these as well.

• Follow Recommended Operational Limits: Some residential pressure washer pumps are designed for intermittent use rather than continuous operation for extended durations. Check your machine’s manual to check its recommended duty cycle and avoid running it for longer than these periods to prevent overheating.
• Don’t Leave Your Pressure Washer Idling For Too Long: Thanks to unloaders, pressure washers can operate in bypass (motor running without the trigger being pressed) for short periods without issue. However, running in bypass for extended periods without cycling fresh water through can cause significant damage to your pump. Water in bypass continually cycles through the pump and will continue to heat up, which can overheat the pump and cause metal components to crack and seals to melt. Also, when the pump overheats, the rush of cold water can cause the hot ceramic pistons to crack. It is best to operate in bypass as little as possible, so keep fresh water flowing through as often as you can!

Summary

Pressure washer pumps are the heart of your cleaning rig, and maximizing its lifespan requires proper maintenance. To ensure your pump remains in optimal condition, adhere to your specific pump's maintenance schedule, make sure your water source is clean, and keep time idling without the trigger held to a minimum. 

If you need parts for a DIY repair or prefer a professional technician to handle the service, we’re here to help. Click here to contact your local dealer for personalized assistance or to schedule pump servicing!