Perform a Pump Oil Change in 4 Easy Steps

A pump oil change should be done every 3 to 5 months to keep equipment running smoothly, safely and efficiently. The high pressure pump inside a hard working pressure washer is literally the heart of the machine. The purpose of the pump is to produce the water pressure which enables you to do the task at hand.

There are many benefits to regularly changing the oil and the most obvious is clean oil keeps a machine lubricated and running properly. When clean oil flows through a pressure washer pump, you will extend its working life (new pressure washers don’t come cheap) and optimize its performance. You’ll get the most out of your hard working machines when you take care of them.

Most pressure washer pumps use a 30w non-detergent oil. This is because most pressure washer pumps use splash lubrication. This is a process that includes rotating “dippers” that throw oil into the pistons and cylinders.1 It is important to use a non-detergent oil in this setting because using an oil with a cleaner (detergent) will foam up when it is agitated by the dippers. Check your pressure washer manual to make sure you are using the right oil.
There are several methods for removing oil during a pump oil change and these are explained in more detail below. The basic procedure is the same regardless of how the oil is extracted;

  1. Run the machine for a few minutes or perform the pump oil change at the end of using the pump. The reason is warm oil traps the dirt better and flows much quicker than cold oil. A word of caution: the unit may be hot to the touch so use caution when removing the drain plug.
  2. Extract the oil from the pump using one of three methods:
    - Drain it from the bottom of the oil pan using the oil drain plug
    - Suction it out, using a suction gun
    - Pump it out, using a hand-operated or electrical suction pump
  3. Put the used oil in a container so that it can be brought to a recycling facility to be cleaned and reused. Used motor oil never wears out, so why throw it out?2
  4. Secure the drain plug. Now it is safe to fill the pump using the oil fill opening. Secure the oil fill cap and you're done!
Pump Oil Change in Pressure Washer

Draining the oil through the drain plug at the bottom of the unit is a quick way to do a pump oil change, not counting the clean-up (if you do make a mess, an oil stain remover may come in handy). Using a makeshift funnel or large diameter plastic tubing can help you “aim” the oil into the correct container. And before you get distracted by the next bright shiny object to cross your path, be sure to replace the drain plug before re-filling the pump with oil. You may laugh but we’ve heard from way too many customers who have forgotten to replace the drain plug to know it can happen to just about anyone.

A suction gun is an airtight cylinder similar to a grease gun. Instead of pushing on the plunger to push something out, you pull a plunger which creates a vacuum to pull something in. Obtain a length of 1/4-inch clear plastic tubing, like the chemical hose you use with a downstream injector, and drop one end through the oil fill opening and attach the other end to the suction gun. Draw the oil out of the crankcase and use the tool in reverse to empty the used oil into a recycling container.

A suction pump (or oil change pump) also draws the oil up a tube through the oil fill opening. The mechanism in a suction pump is different in that it drains the oil directly into an attached container. This oil change pump creates a vacuum either with an electric motor or by the user depressing a handle, as you would with a bicycle pump. A shutoff valve in the tubing allows you to pump up the vacuum, and when you release the shutoff valve, the vacuum draws the oil up through a tube into the container.

A pump oil change doesn’t have to be complicated, nor does it require expensive equipment. Making an oil change easy lends itself to proper pump maintenance. The more pain free and easier it is to change the pump oil, the more likely it is you will do pressure washer maintenance properly and in a timely manner.


  1. What is Splash Lubrication?
  2. Recycling/Disposal of Used Oil — Department of Resources Recycling and Recovery (CalRecycle)