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Pressure Washer Problems: Pump & Water Troubleshooting With Fixes

A pressure washer is an excellent solution if you frequently need to clean your car or the driveway from stubborn dirt deposits. The pump produces a pressurized stream of water at the spray gun, which removes all sorts of dirt. Being a user, you occasionally experience issues related to the pump and the water delivery system and wonder if they can be fixed by yourself.

If your pressure washer leaks water, check the connections at the pump. Check the connections between the pump, high-pressure hose, and spray gun if water leaks from your pressure washer. Make sure the connections are secure, and the seals and O-rings are in excellent shape. If the water pressure is low, check for plugged nozzles and turn the unloader valve to its maximum. If your pump leaks oil or makes strange noises, check the seals and oil them regularly.

In this post, I shall explain how to diagnose any generic pressure washer having problems with the pump or having water leakage issues. You will learn how to troubleshoot and perform these repairs by yourself.

Pressure Washer is Leaking Water

Water may leak from your pressure washer’s connection points. To troubleshoot the water leak, check the pump and spray gun connections individually.

A leak is more likely to arise from one of three connections. The first point of leakage can be the pump itself. The second point can be the pump’s intake and exit hose connections. The spray gun’s connection to the high-pressure hose may also cause water to leak.

● Pressure Washer: Water Leaking from the Pump

If your pressure washer leaks directly from the pump, it’s usually due to worn-out piston seals that need to be replaced.

Most pressure washer pumps use a positive displacement piston mechanism to push the water across the tubing.  A piston seal stops this water from escaping the pump. Over time, these seals are liable to wear out, resulting in a leak. To inspect this, you may need to dismantle the pump’s casing and check for signs of wear on the piston seals.

This is only applicable if you have a plunger pump. Axial and wobbling plate pumps are normally factory assembled and do not allow for disassembly. As a result, seals cannot be replaced independently in such a scenario, and the pump must be replaced to resolve the issue.

● Pressure Washer: Water Leaking from the Hose Connection

If your pressure washer’s hose connections leak, the connectors at these attachments have been damaged and should be replaced.

A connector/pipe coupling links the hose to the low-pressure input at the pump. This coupling has a seal to prevent leakage. If there is a leak at this location, the connector and its seal are most likely damaged. Similarly, if the coupling at the pump outlet’s connection and the high-pressure hose leaks, its outlet seal must be replaced.

● Pressure Washer: Water Leaking from the Spray Gun

If the spray gun on your pressure washer leaks water, inspect the hose-gun connection and tighten it by adjusting the screws. After that, check the hose’s outlet for a damaged O-ring and replace it if required.

Most pressure washers use a press fit to connect the high-pressure hose to the spray gun. You should check to determine if the fit is working properly and the connection isn’t loose. If it contains screws, make sure they are tight enough. If the leak continues after tightening the fit, please check the O-ring at the hose to determine if it is still there. A missing O-ring might have caused this leak.

Seals, gaskets, and O-rings for your pressure washer may be obtained online or through your pressure washer parts dealer.

Pressure Washer: Water Pressure Problems

Here’s how to fix your pressure washer if it’s not generating enough water pressure.

●1. Pressure Washer: Low Pressure

Check for an adequate supply of water and that the entrance line is not clogged with dirt to troubleshoot low water pressure. Also, make sure the nozzle is working correctly.

The pump’s input’s water supply must be enough to produce the necessary pressure. Inspect the inlet hose for kinks. Also, most intake hoses have a debris filter at the pump connection. Examine the filter for any dirt that has been trapped in it. If the problem continues, ensure that you are using the right nozzle and that it is not blocked with debris.

●2. Pressure Washer: No Pressure

Check the water source, hose, and nozzle if your pressure washer loses pressure. Afterward, check the unloader valve and the pump, one of which is at least faulty.

While a loss of pressure might also be caused by debris stuck in the nozzle or by an inadequate water supply. However, the pump and the unloader valve are most likely faulty in this case.  Adjust the unloader valve gently while keeping the pump running and the trigger pressed to check whether the pressure improves. If not, replace the unloader valve, as it’s probably not working. Your pump’s plungers and O-rings may also require inspection for damage.

Additionally, cavitation-induced air bubbles can damage some pump components over time, resulting in pressure loss. Before replacing parts on your pump, consult the owner’s manual. Since most pumps are sold as single units, they cannot be dismantled and can only be changed with new ones.

●3. Pressure Washer: Surging Pressure

If your water pressure suddenly rises, check if the nozzle is damaged. Additionally, the unloader valve should be adjusted to allow more water into the bypass and less into the spray cannon.

The unloader valve on your pressure washer bypasses the high-pressure flow to the pump intake or the water tank instead of sending it to the spray gun. When your unloader is too tight, it hardly bypasses any flow, resulting in high pressure at the gun outlet. Loosening the unloader valve, the flow rate across the bypass would increase, preventing any pressure spikes at the gun. If this doesn’t work, examine your nozzle for obvious signs of damage and replace it if needed.

●4. Pressure Washer: Drops Pressure after a Few Seconds

If your water pressure suddenly drops, it might be due to a blocked nozzle or a leakage in the hose. A poorly set unloader valve might cause this problem.

Contrary to the case of surging, if the unloader is set too loosely, the pressure at the gun can drop. If the setting is too loose, even a small water pressure flow rate can overcome the spring force and engage the bypass. Consequently, water pressure at the gun’s exit falls. You should also examine your hose for any holes or leaks. Make sure your nozzle isn’t clogged with dirt.

●5. Pressure Washer: Strange Noises from Pump

If your pump makes an odd noise, it may be caused by faulty bearings or damaged connecting rods. If it is not properly lubricated, it will also make noise.

Most high-end pressure washers have pumps with oil that can be changed. Plunger pumps are the most common kind. They require regular oil inspections and, if necessary, oil changes. On the other hand, low-end versions use a wobbling or axial piston pump, into which oil is poured during the manufacturing stage and then permanently sealed.

Your pressure washer pump should be maintained every three months, depending on the type. Lack of lubrication causes metal parts to slide against one another, resulting in noise. In such an event, you can disassemble the pump and examine the bearings. If lubricating the pump does not solve the problem, a bearing replacement will almost certainly do the job.

If your axial or wobbling pressure washer pump generates odd noises, replace it with an identical one, as it cannot be disassembled and fixed.

●6. Pressure Washer: Excessive Noise

If your pressure washer is making too much noise, it could be because the pump’s internal parts are damaged, the air is getting into the pump, the pump casing is damaged, or the engine is knocking because of bad fuel.

When the air becomes trapped in a pump, the plungers generate a loud grinding noise, which can cause seals and connecting rods to wear out. If the pump’s casing breaks, it could cause vibrations that would produce a substantial amount of noise.

If you have a pressure washer that runs on gas, check the fuel quality going into the engine. To eliminate engine knocking, I recommend using ethanol-free, unleaded fuel with an octane number of at least 87.

●7. Pressure Washer: Oil Leaking from the Pump

A pump that leaks oil almost always has a defective seal or a worn-out O-ring. If possible, dismantle your pump and replace all of the seals manually. If under warranty, contact the manufacturer for support.

If your pump has replaceable oil and your warranty expired, you can consider dismantling it. If you don’t possess the necessary skills, hire a professional or contact your manufacturer.  To replace the oil seals, I recommend purchasing an oil seal kit containing seals and rings in various sizes.

While reassembling, make sure that all bolts and fittings are properly tightened. To avoid further oil leaks, never expose your pressure washer to high temperatures that can easily degrade rubber components.

If your pressure washer’s pump is permanently sealed, the only option is to replace the complete pump.

●8. Pressure Washer: Water in Oil

Water enters the pressure washer if the pump has a faulty oil seal. You should replace its seal in such an event.

When water enters the pump oil, it turns milky. A faulty oil seal might cause this. The entire pump must be disassembled to replace the seal, including the housing, valves, seals, and rings.

I would only do this once the pump’s warranty has ended. Under warranty, the pump manufacturer should fix this. This is only applicable to pressure washers equipped with an oil-changeable pump. Most low-cost pressure washers have a permanently sealed pump that can only be replaced as a whole if it gets damaged or broken.

●9. Pressure Washer: Soap Not Dispensing from Reservoir

Check the nozzle size if your pressure washer isn’t collecting soap from the reservoir. You must also examine the soap injector kit and replace any damaged or worn-out parts.

For the soap injection function, the owner’s manual recommends a certain type of nozzle that provides appropriate suction pressure for the detergent. Make sure you’re using the proper nozzle. If it doesn’t work, examine your soap injection kit to ensure the nozzle isn’t clogged with debris. A chemical injector repair kit will provide you with all the spare components needed.

Pressure Washer troubleshooting table:

The pressure washer is not producing high pressure
Hose with small diameter
Replace your hose with a 1″ (25mm) or 5/8″ (16mm) hose
Restricted water supply to the washer
Check for the kinks and leaks in the hose
Inadequate water supply
Ensure the water source is unobstructed and fully turned on
Clogged intake filter
Remove the filter and rinse it with warm water
Air in the pump
Ensure that the hose and fittings are airtight. Shut off the washer and squeeze the trigger until water flows steadily from the spray tip
The suction tube or detergent bottle is not connected properly
Install the suction tube and detergent bottle correctly
Detergent too thick
Dilute the thick detergent by adding water
Obstructed spray tip
Remove the debris with a needle
No pressure tip on the wand
Install a suitable pressure tip at the end of the wand
If your model has a belt, it can be loose.
Tighten or replace the belt.
Pulsing pressure washer (output pressure varies high and low)
Inadequate water supply
Ensure that the water source is fully on and check the hose for kinks and blockage
Obstructed spray tip
Remove the debris with a needle
Pump sucking air
Ensure that the hose and fittings are airtight. Shut off the washer and squeeze the trigger until water flows steadily from the spray tip
Clogged intake filter
Remove the filter and rinse it with warm water
Calcified hose, tip, or trigger
Clean the hose, pressure tip, or trigger with vinegar or a cleaner designed for this purpose
Noisy Pump
Air in the pump
Ensure that the hose and fittings are airtight. Shut off the washer and squeeze the trigger until water flows steadily from the spray tip
Clogged inlet filter
Remove the filter and rinse it with warm water
Pump leaking water
Damaged or worn water seals
Replace the seals with new ones or call a professional
Loose fittings
Ensure that all the fittings are tight
Erratic water pressure, changing up and down
Unloader valve
Check and clean the unloader valve. If in bad shape, replace it
No output pressure. Or the motor stops when using the trigger (electric models)
Unloader valve
Check and clean the unloader valve. If in bad shape, replace it

● Gas Pressure Washer Engine troubleshooting table:

The motor won’t start
The power switch is in the “OFF” or “0”  state
Turn the power switch “ON” or “1”
Cord not plugged
Plugin the power cord
Damaged, too long, or improper extension cord
Replace the existing cord with a 25′ (7.6m) 14 AWG cord or a 50′ (15m) 12 AWG cord
Inadequate power from the electrical outlet
Plug the cord into a different outlet
The pressure washer circuit breaker tripped
Please wait for the washer to cool down and restart it
The motor buzzes but fails to run
Loss in voltage due to the extension cord
Plug the unit directly into the outlet without an extension cord. If the problem isn’t solved, replace the extension cord
Low supply voltage
Ensure that only the pressure washer runs on that circuit at the time of use
Residual pressure in the system
Shut off the washer and squeeze the trigger to release pressure
Residual friction among the internal components
Cut the water supply and turn the machine ON for 2 to 3 seconds. Try it a couple of times or until the motor starts. Don’t let the machine run dry for more than 3 seconds.
Unit not used for long periods
I recommend calling a professional for help
Motor not working
Faulty Timer
Disconnect the leads from the timer. If your pressure washer doesn’t turn off after the time out, the timer is faulty, and you need to replace it.

● Electric Pressure Washer Motor troubleshooting table:

Leaks in the spray wand, spray tip, or extension
Damaged or broken O-rings or plastic insert
Replace the worn O-rings or call a professional
Pressure washer pump dripping oil
Worn or damaged oil seals
Inspect the oil seals and replace them if worn
No water from the washer outlet
The water supply is off
Turn the water supply ON
Kink in the hose or faucet not fully open
Remove any kinks and debris from the hose or water lines. Check and fully open the faucet.
The motor won’t start
Check the battery
Check if the battery is charged correctly. Charge or replace when in bad condition. Examine the battery terminals for a proper connection. Clean if needed.
Check the fuel filter
Clean the fuel filter if dirty. In that case, check the gas tank, as this is the most likely culprit.
Check the gas supply
Check the fuel level and add if needed. Ensure that the gas can flow to the carburetor. Remove any blockage.
Check the Air-filter
Clean the air filter. Replace it when it is in bad condition or it is a paper air filter.
Check the carburetor
Remove and clean the carburetor with some carb cleaner. It is also possible to clean it without removing it.
Fuel gap blocked
Check that the hole in the fuel cap is open. Clean if needed.
The engine is stalling, or starts and stops
Check the carburetor
Remove and clean the carburetor with some carb cleaner. It is also possible to clean it without removing it.
Air filter
Clean the air filter. Replace it when it is in bad condition or it is a paper air filter.
Check for bad gas
Suppose you have old gas, more than a few months old. It can turn bad. Drain and replace the gas. Next time add a fuel stabilizer.