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 take 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 washer pump oil.
Full & Low Engine Oil Level
Gas Powered or Electric?
Think of a pressure washer as two separate 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 a 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. A 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 changes are required. You guys are spoiled, really you are!
That said, if your pressure washer 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 owner’s manual for recommendations. Some manufacturers actually void the 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 – Clean with cloth and refit (don’t thread home threaded dipsticks when checking). Remove dipstick once again and read oil level.
Locate Max (full) & Min (low) – Dipsticks commonly have two 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”.
Some dipsticks employ a third dipstick mark – the hatched zone. It’s located between the full and low oil level marks. Hatched zone identifies an oil level that’s acceptable, it’s neither full nor critically low. Adjusting the oil so it reads full is preferred, but it is safe to run an engine in the hatched area.
Read – Oil level is critically low, add oil.
Read – Oil level is correct
What Engine Oil Type For Pressure Washer?
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 that 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 Pressure Washer Engine Oil?
Engine oil should be changed at least once a year, and at the start of the new season is best. If your 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 the first oil change after 5 hours of operation.
How To Change Pressure Washer Engine Oil?
Changing the oil is a nice easy Saturday afternoon chore that won’t take longer than thirty minutes.
Here are the tools and parts needed:
- About a quart of 5W30 oil
- Wrench set
- Oil pan drain
The oil change process is as follows:
- Warm the engine (helps draining process)
- Park on level ground
- Remove the dipstick
- Place the oil catch under the oil drain (may need to position a plastic sheet to guide oil to the catch)
- Remove oil drain & allow drain fully
- Refit oil drain
- Add half a quart of oil and check level
- Continue to add oil in small amounts and check level
It’s easy to overfill the engine oil as these small engines hold 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 overfill, no problem just drain a little back out.
How Can You Tell Pressure Washer Maintenance Free Pump?
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 the oil level and general condition.
No Oil Drain – If your pump doesn’t sport any of the features, described, it’s likely an oil for life pump.
Checking Pressure Washer Pump Oil Level
As you know, most pressure washer pumps require no maintenance at all, not even an oil check. This type of 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.
If however, your pressure washer pump does require maintenance, it will likely employ a small sight glass on the sidewall of the pump. The sight glass allows the operator to check the pump oil level at a glance.
With the wash-off, the pump oil should rest 3/4 way up the window. Lower than this means a top-up is required. Pumps, unlike engines, don’t use a lot of oil, so if your pump is low on oil, it may indicate an oil leak, a worn-out seal is a usual suspect.
This oil level is a touch low.
When To Change Pressure Washer 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 Pressure Washer Pump Oil?
Changing the oil isn’t difficult, but obviously only possible if your wash pump is fitted with 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 draining 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!
You may also find “Pressure washer troubleshooting” useful.
- About the Author
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John Cunningham is an Automotive Technician and writer at Lawnmowerfixed.com.
He’s been a mechanic for over twenty-five years and shares his know-how and hands-on experience in our DIY repair guides.
Johns’s fluff-free How-to guides help homeowners fix lawnmowers, tractor mowers, chainsaws, leaf blowers, power washers, generators, snow blowers, and more.