How to change the oil on a pressure washer

July 28, 2025

BISON Santy

Hello, I am Santy, the funder of bisonclean.com. I have been in cleaning machinery field for more than 5 years now, and the purpose of this article is to share with you the knowledge related to pressure washer from a Chinese supplier's perspective.

Changing the oil in your pressure washer is a simple yet essential task that keeps the engine well-lubricated, reduces wear, and helps prevent breakdowns. This routine maintenance enhances performance and extends the life of your machine.

What you need to know is that the oil should generally be changed every 50-100 hours of use, although, of course, the actual time should follow the guidelines in your owner’s manual. In this article, you’ll learn how to change your pressure washer’s oil step by step to keep it running at its best.

Understanding your pressure washer’s oil requirements

The type of washer—gasoline or electric—determines the oil requirements and whether oil changes are even necessary.

Types of pressure washers

Gasoline pressure washers: Their engines rely on oil to lubricate internal components, reduce friction, and prevent overheating. Since they operate under high pressure, changing the oil is very useful in avoiding overheating and mechanical failure.
Electric pressure washers: Electric models use motors that do not require oil for lubrication, so oil changes are not needed.

Tools and materials required to change the oil

New engine oil: Use the oil recommended in your pressure washer’s manual. Most gasoline models use SAE 30 or 10W-30, but always double-check the specifications for your unit.
Oil drain pan: Needed to catch old oil as it drains from the engine. You can use a dedicated oil pan or any clean container that holds at least 16–24 ounces.
Funnel: A funnel helps pour new oil into the engine without spilling. A narrow or long-spout funnel is useful if the fill port is hard to reach. To avoid contamination, using a clean funnel dedicated to oil changes is best.
Wrench or socket set: Required to remove the oil drain plug. Most models use a 10mm to 14mm wrench—check your manual for exact sizing.
Rags or paper towels: For wiping up spills and keeping the work area clean. Cleanliness helps prevent dirt from entering the engine.
Oil filter (if applicable): Some models have an oil filter that should be replaced during oil changes. Refer to your manual to determine if this applies.

Step-by-step guide: How to change the oil in a pressure washer

Step 1: Prepare for the oil change

Let the engine cool down: If the pressure washer has been running, turn it off and let it cool for 10–15 minutes. This prevents burns and allows the oil to drain more effectively.
Disconnect the spark plug: For safety, unplug the spark plug wire to prevent accidental engine startup while you work.
Set up on a level surface: Place the pressure washer on a flat, stable surface like a driveway, garage floor, or workbench. This helps oil drain evenly and reduces the risk of spills.
Prepare a well-ventilated workspace: Work in an open or ventilated area to avoid inhaling fumes and ensure a safer environment.
Locate the drain plug and oil fill cap: Use your owner’s manual to identify where the drain plug and fill cap are located. The drain plug is typically under the engine, while the oil fill cap is on the side or top of the crankcase.
Wear safety gear: Put on gloves to protect your hands from hot parts and used oil. Safety glasses are also a good idea to guard against splashes.

Step 2: Oil change steps

Warm up the engine: Start the engine and let it run for a few minutes to warm up. This thins the oil, making it easier to drain. Afterward, turn off the engine and let it cool slightly until it’s safe to handle.
Remove the oil fill cap: Take off the oil fill cap—usually located on top of the engine—to allow air into the crankcase. This helps the oil drain more smoothly.
Position the oil drain pan: Place an oil drain pan or container directly under the drain plug. Make sure it’s centered and large enough to catch all the used oil.
Remove the drain plug: Using a wrench or socket set, carefully remove the drain plug and allow the oil to drain fully. Let it sit for a few minutes to ensure all the old oil is expelled.
Clean the drain plug and area: Once the oil has drained, wipe the drain plug and the surrounding area with a clean rag or paper towel to remove any residue or debris. Check the plug for wear or damage.
Replace the drain plug: Reinstall the clean drain plug and tighten it securely. If your washer uses a sealing washer, consider replacing it to ensure a tight fit. Avoid overtightening to prevent damage.

Step 3: Adding new oil

Add new oil using a funnel: Insert a clean funnel into the oil fill opening and slowly pour in the new oil. Refer to your owner’s manual for the correct oil type and capacity.
Check the oil level with the dipstick: As you fill, periodically check the level using the dipstick. Wipe it clean, reinsert it fully, then remove it to get an accurate reading. Avoid overfilling—if the level is too high, drain the excess to prevent leaks or engine damage.
Dispose of used oil properly: Take the used oil to an auto parts store or recycling center that accepts motor oil. Never pour it down the drain or throw it in the trash—improper disposal harms the environment and may violate local laws.

Step 4: Final checks

Clean any spills: Wipe away any oil spills around the engine with a rag or paper towel. Keeping the area clean prevents slips and protects the engine from dirt and buildup.
Reconnect the spark plug: Reattach the spark plug wire securely to ensure the engine is ready to start and operate safely.
Run the engine briefly: Start the engine and let it run for a few minutes. This helps circulate the new oil. Watch for leaks around the drain plug or oil fill cap, and listen for any unusual noises. If you spot any issues, turn off the engine and make necessary adjustments.

Step 5: Post-oil change procedures

Perform a final oil check: After the engine has run briefly, turn it off and recheck the oil level with the dipstick. Add oil if needed to bring it to the recommended level.
Log the maintenance: Record the oil change in your maintenance log, noting the date, oil type used, and total engine hours. Keeping records helps ensure timely maintenance in the future and avoids operating errors.

Maintenance schedule

Oil change intervals

BISON recommends that the oil be changed at least every 50-100 hours of use or at least once a quarter. Especially for pressure washers that are used frequently or used for heavy-duty applications, the oil needs to be changed more frequently.

Signs you may need an early oil change

Reduced engine performance – Rough idling, power loss, or hesitation can indicate old or ineffective oil.
Dark or dirty oil – Oil that looks gritty, smells burnt, or has turned very dark should be replaced.
Excess exhaust smoke – Thick or unusual smoke may mean the oil is contaminated or low.

Conclusion

Regular oil changes are crucial to keeping your pressure washer operating efficiently and extending its lifespan. By following the correct procedures, using the recommended oil, and performing routine maintenance, you ensure your machine runs smoothly, avoids costly repairs, and delivers peak performance during every use.

At BISON, we believe in the power of proactive maintenance and offer a full range of premium pressure washers built for durability, performance, and ease of service. Our high-quality products, combined with reliable support and flexible OEM/ODM solutions, make us the ideal partner for distributors and dealers worldwide.

Start business cooperation with BISON pressure washer factory today to provide your customers with first-class pressure washer solutions and upgrade your product models backed by trusted factory support and excellent service.

FAQs about change the oil on a pressure washer

Can I use car engine oil in my pressure washer?

Car engine oil isn’t ideal for small engines. Use the recommended oil, like SAE 30 or 10W-30, as specified in your manual.

Can I change the oil without removing the oil filter?

No. If your unit has an oil filter, it should be replaced with every oil change to keep the engine running efficiently.

Why is my drain plug difficult to remove?

It may be stuck or rusted. Apply penetrating oil, wait a few minutes, then try again. If it’s damaged, replace it or seek professional help.

Why won’t my engine start after an oil change?

Check the spark plug connection, oil level, and allow time for oil circulation. If it still won’t start, consult a professional. For more knowledge about pressure washer won’t start, please check out “What to do if your pressure washer won’t start“.