What type of engine oil should I use in my pressure washer?

This article provides a detailed guide on selecting and using the right engine oil for your pressure washer, taking into account initial use temperature conditions and ongoing maintenance requirements.

Environment

This article applies to all gas-powered pressure washers and covers engine oil only. Pump oil is separate from engine oil. For oil maintenance on professional models with a triplex pump, see How do I perform oil maintenance on a pressure washer triplex pump? Residential pressure washers with axial cam pumps are sealed and do not require pump oil maintenance.

Initial oil use and break-in period

SAE 30 for break-in: Pressure washers are shipped with SAE 30 oil, which is ideal for the initial break-in period. It is important to use this oil because it helps properly seat the engine's internal components.

First 5 hours of operation: Do not switch to a synthetic oil until the first 5 hours of operation have been met.

Switching to synthetic oil

After break-in: Once your pressure washer has operated for the first 5 hours, switching to a synthetic oil is recommended. This type of oil offers better performance in a wide range of temperatures and generally provides superior engine protection.

Regular oil changes: Change the oil every 20 hours of operation or at least once per season, whichever comes first. Regular oil changes ensure that your engine remains in good working condition and extends its lifespan.

Refer to the chart below to select the proper engine oil for the temperature range of your operating environment.

• 5W-30 Synthetic can operate in a wide range of temperatures, from as low as -22°F (-30°C) to as high as 104°F (40°C).
• 10W-30 can also operate in a wide range of temperatures, but may struggle in colder conditions.
• SAE 30 operates well at high temperatures, but using it below 50°F (10°C) may result in a hard start.

Engine oil capacity

Pressure washer engine oil capacity is based on the pressure washer's PSI rating.

• If the pressure washer is less than 3800 PSI, its engine oil capacity is 20 oz. / 0.6 liters
• If the pressure washer is 3800 PSI or greater, its engine oil capacity is 37 oz. / 1.1 liters

Oil capacity is a general fill amount. Use the engine oil dipstick, if equipped, or the oil fill opening as shown in the owner’s manual to verify the final oil level and avoid overfilling. Pressure washer owner’s manuals can be found on Generac’s product lookup page.

Selecting high-quality oil

Oil specifications: Look for synthetic oil that meets ILSAC GF-2 or API certification. These specifications ensure that the oil provides the necessary protection for your pressure washer's engine.

Detergent oil use: Use high-quality detergent oils that are classified for service SF, SG, SH, SJ, or higher. These oils contain additives that help protect the engine by cleaning and preventing the buildup of deposits.

Avoid special additives: Do not use oils with special additives because they might not be compatible with the engine of your pressure washer and could lead to increased wear or damage.

Changing the engine oil

For a complete step by step guide on how to change the pressure washer's engine oil, consult the owner's manual: How Do I Find the Spec Sheet and User Manual for My Pressure Washer