How to Change Oil in a Pressure Washer
Tips & Tricks

How to Change Oil in a Pressure Washer

Just like in automobiles, all motor-powered require a regular oil change. The degraded oil affects the performance when you leave it in the pump for too long. If you are new to oil change are wondering what oil you should use in your pressure washer, you have come to the right place.

Keep reading to learn how to carry out a pressure washer oil change.

How often should I change the oil in my pressure washer?

During normal service, replace the oil every 200 to 250 work hours, about every three months if you use your machine often, and at least every year if not. One way to remember to change the oil in your pump is to schedule it and change the oil in the pressure washer’s engine.

Be sure to consult your manual to learn whether and when pressure washer pump oil should be changed and the correct oil for your pressure washer. During normal service, replace the oil every three months if you use your machine often, and at least every year if not.

Note: One way to remember to change the oil in your pump is to schedule it and change the oil in the pressure washer’s engine.

What kind of oil do I put in my pressure washer?

All-purpose engine oils are mostly used in temperate conditions and are usually the SAE30 type is recommended for temperatures above 40ºF. However, if temperatures fall below 40 ºF, it is recommended that you use the 10W-30 oil to help your power washer start better.

A modern engine pressure washer such as the Ryobi pressure washer uses detergent oil because it has an oil filter. That’s why it is recommended to use non-detergent oil in pressure cleaner pumps. If you use detergent oil in a pump, all the contaminants it cleans off the surfaces will be flowing through the oil.

A non-detergent oil of 30w is commonly used in pressure washer pumps. Splash lubrication is the most common method of lubrication for pressure washer pumps. The oil is thrown into the cylinders and pistons by rotating the dippers in this process.

Note: Always use oil specifically designed for pressure washer pumps. Good pressure washer pump oil is non-detergent, non-foaming, and has rust inhibitors.

How to change the oil in a pressure washer

To change the pump oil;

  • Place the bucket or pan under the pressure washer drain plug.
  • For the location of the plug, refer to your pressure washer owner’s manual.
  • Remove both the oil drain plug and the pump oil filler cap.
  • Allow the oil to drain completely from the pump.
  • To catch the oil without making a mess, on some models, you may have to use a funnel or piece of tubing to guide the used oil to the drain pan.
  • Replace the drain plug and fill the pump with DP70 pump oil.
  • Use only the quantity specified in your pressure washer’s manual for your pump.
  • If you’re unsure, measure how much oil you drained and replace it with that amount.
  • Most pumps have an oil window or sight glass on the side of the pump, with a mark or red dot indicating the proper level for the oil.


  1. Running your pressure washer for a few minutes will help you remove dirt and water from the machine.
  2. Once the oil from your pump has been emptied into a tray, you can use it.
  3. Add your new oil, non-detergent-based, to your pump until about 34 percent of the way full.
  4. Set your pressure washer upright before closing your pump firmly.

How much oil goes into my pressure washer?

Never overfill the pump with oil. This could lead to leaks caused by damaged seals. The average pressure washer uses about five oz. of pump oil per cycle. Therefore, the oil change can be done with a single bottle of pump oil. In addition, there is no oil filter in most pumps, so the oil is non-detergent.

Changing or adding oil to an engine crankcase should not be done overfilled. Smoke, hard starting, spark plug fouling, and oil saturation can result from overfilling oil. Also, if you do not connect and turn on the water supply before using the pressure washer, the pump will be damaged.

What happens if you don’t change the oil in your pressure washer?

A pump needs oil to lubricate its internal surfaces to reduce friction, wear, and heating of the parts as they move. The purpose is to prevent early failure. In addition, the oil is critical for pump performance:

So what are the reasons you should care about pump oil?

To maximize component life

It acts as lubrication for moving parts, reducing friction between them. This reduces heat. Excess heat is a problem because it expands the seals, making them at risk of cracking.

Warranty requirements

Check your User Manual to see if your warranty is void if you fail to change the oil in a pressure washer. It is easy to see dirty unchanged oil for warranty repairs when you take it in.

The cost to rebuild a pump back from failure is expensive

Axial pressure washer pumps such as Briggs and Stratton pressure washers might not be worth repairing depending on the failure. Failure to change the oil will result in a dirty unloader valve that you will have to tear down the pump and clean or replace. That repair is no problem. If you have cracked or damaged seals or O-rings, you have to replace them.

But if you need to start replacing pistons or the swashplate, you will be better off just replacing the entire pump. Rebuilding a triplex pump such as a Generac pressure washer can cost up to $500.

When Should I Change the Oil in My Pressure Washer Pump?

Change your pump oil if it looks milky, changes color, or has visible particles. So how do you know when to change the oil?

Maintenance/ Warranty consideration

Your user manual will specify an oil change based on hours used. Keep track of the hours you have used your machine and change the oil when needed.

The oil is leaking

If you notice a regular oil leak from the pump, you can be sure it is low on oil and will need to be repaired or replaced – and oil is added often if you must use it before the repair.

The oil is a milky color

If the oil is a milky color, you should change it. To check the color, drain a tiny amount out to check for quality. It is a safe bet to change the oil in any of these situations.

Pressure washer Maintenance

Running clean oil in your pressure washer’s pump is one of the best ways to ensure your machine’s long life and efficient performance. The pump is the heart of your pressure washer and runs at high temperatures.

The pumps of most pressure washers under $400 have a pump that does not require maintenance. They are filled with oil at the factory and permanently sealed. The pump oil should be changed regularly with quality pressure pump oil and kept at the recommended level in other pumps.

Never pour used oil into a storm drain or sewer. Please dispose of the old oil properly by recycling or taking it to a used oil collection center. Always follow manufacturer recommendations and instructions for types of oil, locations of oil filler caps and drain plugs, and oil quantities. Lastly, this guide can be used in a wide range of pressure washers, such as the Honda pressure washer, Craftsman, and Dewalt.