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How to Diagnose Pressure Washer Pump Problems

Pressure washers are great. They help us clean our patios, cars and many other outdoor areas. Often, over time, wear and tear can lead your trusted pressure washer to fail. A somewhat common fault of a pressure washer is the pump.

This article can help you identify the most common indicators as to when your pump has begun to develop a fault. We will look at three varying signs that your pressure washer pump could be faulty.

Following this guide will give you some insight on how to easily diagnose and possibly service and repair your pressure washer.

Safety First! Please make sure that you’ve switched off your appliance and disconnected it from the mains before beginning any repair.

Starting our list, leaks are a very common problem with pressure washers. These are most likely caused because of perished seals or faulty components.


If your leak is coming from the hose, normally this is not something to panic over, most commonly a leaking hose is a clear sign of a worn or perished O-ring or gasket. To repair, you can simply replace the old perished gasket with a new one.


A bit more tricky are these two areas where the washer could fail leading you to be soaked. These are the:

The cause of these could be as simple as trapped water that has not been drained before winter. If the water freezes it’ll expand resulting in the plastic parts becoming damaged.

Identifying Leaks

To find the home of the leak, you will want to first remove the case of the pressure washer, apply the water hoses and turn the water on. However do not plug the machine in. The water pressure should now identify which area the leak is originating from.

If you can identify that a leak is coming from any area of the cylinder head, the pressure which stops the machine from running when not in use will quickly disperse. This then will lead to the motor to restart or pulse.

Another cause resulting in your motor to pulse is water starvation, caused due to a blocked filter found on the inlet. To service, simply remove the filter and clean out the blockage. This should be done if the washer is pulsing and not leaking.

If your washer is suffering from low pressure problems then you’ll struggle to get the right power to clean any dirt. A common cause of low pressure is a perished O-ring. This tiny rubber gasket helps seal the inside of the pistons or valve. To resolve the problem you will need to replace the faulty part.

However you could find that the seal is fine. If this is the case then don’t fret because the fault is being caused by dirt or some other kind of blockage. Cleaning this out should help restore your machine's pressure.

There you have it! Some simple tips into diagnosing and resolving any faults you are having with your pressure washer. For more care and maintenance tips and how-tos don’t forget to check out our other articles in our Advice Centre.

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