Does Pressure Washer Need Oil?

Pressure washers generally don't get a ton of use, and maintenance isn't seen as a priority. But like all kit, they do need a little love, and you're correct, the most important maintenance an operator can do is a simple oil level check.

The average size gas powered pressure washers takes one quart of 5W30 engine oil and will require scheduled oil maintenance. Pressure washer pumps, including electric models, use Non Detergent (ND) oil and most don’t require maintenance.

In this post you'll learn how to check and add pressure washer engine oil. You'll also learn how to check your pressure washer pump oil, or if you even need to. I'll also cover when and how to change both engine and pressure water pump oil.

Power Washer engine oil dipstick oil level low

Low oil kills engines

Gas powered or Electric?

Think of a pressure washer as two sperate machines working together.

First off, you have the pump. As it turns, it converts water into high pressure water. A pump therefore requires a source of power to produce water pressure.

And the two most common ways to power a pump, are gas engine and an electric motor. 

If your pressure washer is Gas powered then yes, it requires oil level checks and oil changes. More on this below. If your wash is electric, then obviously there's no engine oil maintenance required, electric motors don't use oil for lubrication. 

A water pump fitted to either gas or electric does contain oil. It uses a Non Detergent grade (ND) oil which employs an anti-foaming agent. An non detergent oil is used, because a pump doesn't employ an oil filter to clean the oil.

However, most modern pressure washers, gas and electric don't require any pump maintenance. So no oil checks or changing required. You guys are spoiled, really you are!

That said, if your pressure is larger than most it may require pump oil changes. I'll show you how to spot an oil changer from a maintenance free pump and cover changing oil below.

Always check your owners manual for recommendations. Some manufacturers actually void warranty if you attempt to change the pump oil.

Checking Gas pressure washer engine oil level

Engine oil should be checked ideally every time the gas tank is filled. It's a great habit to get into, and it only takes a moment.

Check the oil as follows:

  • Park washer on level ground & engine off
  • Allow engine a moment to cool
  • Locate dipstick & remove
Locating power washer dipstick

Locate Dipstick

  • Clean with cloth and refit (don’t thread home threaded dipsticks when checking)
  • Remove dipstick once again and read oil level
Power washer dipstick oil level correct

Oil level correct

Dipsticks commonly have three markings. An upper mark, indicating oil full and often identified by a simple notch or letter "F" (full) or word "Max".

A lower dipstick mark, obviously indicating oil level critically low, it's identified by a notch or letter "L" (low) or the word "Min".

Power washer dipstick full and low level markings

Locate Min (low) Max (full) marks

And finally between these two marks, upper and lower, we have a hatched area. It identifies and oil level that's acceptable.

What engine oil type?

Most pressure washers are quite happy with 5W30 engine oil. It's a synthetic blend used in many car engines.

It's a superior oil that offers low temperature start protection and higher temperature protection. It also contains a detergent which helps break down harmful crankcase acids.

You'll find a link to this oil type here on the "Power washer maintenance tools page".

When to change engine oil

Engine oil should be changed at least once a year, and at the start of the new season is best. If you pressure washer sees a ton of action, then it needs to be changed every 50 hours of operation.

If your pressure washer is new, make that first oil change after 5 hours of operation.

How to change pressure washer engine oil

Changing the oil is a nice handy Saturday afternoon chore that won't bit you in the ass.

Here’s the tools and parts needed:

  • About a quart of 5W30 oil
  • Wrench set
  • Oil pan drain

The oil change process is as follows: 

  1. Warm the engine (helps draining process)
  2. Park on level ground
  3. Remove the dipstick
  4. Place the oil catch under the oil drain (may need to position a plastic sheet to guide oil to the catch)
  5. Remove oil drain & allow drain fully
  6. Refit oil drain
  7. Add half a quart of oil and check level
  8. Continue to add oil in small amounts and check level
Power washer oil draining

Drain while warm

It's easy to overfill the engine oil as these small engines hole very little oil. Too much oil can damage the motor, cause engine to smoke, oil leaks even result in a no start. If you do over fill, no problem just drain a little back out.

checking pressure washer pump oil level

As you know, most pressure washers pumps require no maintenance at all, not even an oil check.

Power washer pump

Maintenance free pump

This type pump may be referred to as an oil for life pump. It really means the pump has been designed to last x number of hours and when it gives up, it's replaced not repaired.

In fact, you'll find most oil for life components won't even offer internal parts for purchase.

How can you tell if pump is maintenance free?

Pumps that require oil changes and oil level checks will have an oil drain plug and an oil fill plug. They may also employ a sight glass to check oil level and general condition.

Power washer pump

No oil drain

If your pump doesn't sport any of these features, it's likely it's an oil for life pump.

When to change pump oil

Oil is generally changed by the passing of time or hours worked. Pumps that allow for oil changes, usually recommended a change every 100 hours or every 12 months whichever arrives first.

How to change pump oil

Changing the oil isn't difficult, but obviously only possible if you wash pump is fitted with a drain and fill points.

You'll find a link to a quality pump oil together with all the tools you'll need here on the "Power washer maintenance tools page".

Tools and supplies you’ll need:

  • 1 quart of ND anti foaming pump oil
  • Wrench selection
  • Oil catch 

The drain process is as follows:

  • Run engine a while to warm oil
  • Park wash on level ground
  • Remove top oil fill plug
  • Position oil catch, remove oil drain bung and allow drain completely
  • Refit drain bung
  • Add oil quantity as per owners manual. Or fill until oil half covers sight window. Pumps are generally filled to 3/4 capacity
  • Don’t fit the drain plug just yet

To help reduce aeration (trapped air pockets in the oil), we have one final step.

Turn over the engine without starting the engine (remove spark plug wire). This helps distribute oil throughout the pump and drive air out. Now go ahead and fit the fill plug, nice work!

For parts and tools, check out  "Pressure washer tools page".

You may also find "Pressure washer troubleshooting" useful.

Other pressure washer posts you may find helpful:

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Auto Technician and Writer at Lawnmowerfixed | Website

John Cunningham is an Automotive Technician and writer on Lawnmowerfixed.com. I've been a mechanic for over twenty years, I use my knowledge and experience to write "How to" articles that help fellow gear-heads with all aspects of mechanical repairs, from lawn mowers to classic cars.