Read the manual thoroughly and understand all of the instructions, cautions, and warnings before using this equipment. If any section of the manual is not understood, contact your nearest authorized dealer, or contact Generac Customer Service at 1-888-436-3722 (1-888-GENERAC), or www.generac.com with any questions or concerns.

Changing the oil and oil filter

Generator owners should reference these articles before changing the oil:

Maintenance schedule:

• Oil changes are listed as part of a generator’s maintenance schedule. See Where Can I Find the Maintenance Schedule for My Generac Home Standby Generator? for more information.
• If the generator is running for extended periods during an outage (continuous use), shut it down every 24 hours to check oil levels. See Continuous use maintenance for home standby generators for more information.

Oil type and filter part number:

• Generac recommends using Generac 5W-20 full synthetic oil for all home standby generators, regardless of temperature.
• Oil filter part numbers are listed in the owner’s manual. See How do I find an oil filter for my home standby generator?

Note: 5W-20 synthetic oil is only used after the break-in period, which is the first 25 hours of run time. Do not use synthetic oil during the break-in period. Generators ship from the factory from with 5W-30 conventional oil. Review your installation manual to confirm the correct oil for your exact unit.

Maintenance safety: Owners should reference What Safety Precautions Should I Take When Performing Maintenance on My Generator? to ensure maintenance is performed safely.

Maintenance kits: Generac sells maintenance kits that bundle OEM parts for maintenance tasks. See What Are Generator Maintenance Kits? for more information.

Authorized service dealers: While generator owners can certainly perform maintenance tasks, scheduled maintenance tasks can also be completed by a certified service dealer. See How Can I Find a Generac Service Dealer in My Area? for more information.

 

Environment

If the generator has been running in a power outage, refer to the "Shutting the Generator Off" section in How Do I Shut Down My Generator When It’s Powering My House (During an Outage)? 

If the generator has not been running in a power outage, refer to the instructions below for your generator model.

Guardian series generators

Note: The oil change instructions below apply to 10 kW - 26 kW Guardian series generators manufactured after 2017.

Video instructions

 

How to change the oil and oil filter on a Generac Home Standby Generator (written instructions): 

Note: If the generator has been running in an outage, refer to the "Shutting the Generator Off" section in How Do I Shut Down My Generator When It’s Powering My House (During an Outage)? Otherwise, proceed to step 1.

 

1. Lift the generator's lid and press the MANUAL button on the control panel to start the engine.

2. Let it run for 3-5 minutes or until the engine is thoroughly warmed up.

3. If running during a utility outage, set generator's the generator's main line circuit breaker to OFF (If not running during a utility outage, skip to step 6).

4. Set the utility main line circuit breaker to OFF.

5. Allow the generator to run and cool down for five minutes with no load applied.

6. Then, press the OFF button on the control panel to shut down the engine.

7. Allow the generator to cool for another five minutes before working on it.

8. Remove the front panel when the unit has cooled. Pull oil drain hose (A) free of retaining clip. Prepare a suitable container to drain the oil into, remove cap from oil drain hose and drain oil. 

 

Note: It is not uncommon to notice a milky sheen in used oil: What Would Cause My Generator Oil to Turn a Milky Color?

 

Oil Filter and Drain Location (10 kW):


Oil Filter and Drain Location (13–18 kW):


Oil Filter and Drain Location (20–26 kW):

9. After all the oil has been drained, reinstall the cap onto the oil drain hose and secure the hose to the retaining clip.

10. Remove the oil filter by turning it counterclockwise.

11. Screw the new filter on by hand until the gasket lightly contacts the oil filter adapter.

12. Then, tighten the filter an additional three quarters to one full turn. Confirm it is tight and secure.

13. Remove the oil fill cap and fill the engine with the recommended amount of oil, referencing the table below:

 

Guardian Series Power Rating	10 kW	14/18 kW	20–26 kW
Oil capacity including filter	Approx. 1.1 qt (1.03 L)	Approx. 2.2 qt (2.1 L)	Approx. 1.9 qt (1.8 L)

 

Oil fill location (10 kW)

Oil fill location (14 kW - 18 kW)

Oil fill location (20 kW - 26 kW)

14. Once the appropriate amount of oil has been added, secure the oil fill cap and press the MANUAL button on the control panel to start the engine.

15. Run the generator for one minute and check for leaks.

16. Press the OFF button on the control panel to stop the engine and wait five minutes.

17. Inspect the oil level using the oil dipstick and a clean cloth. 

18. If needed, add more oil as needed. DO NOT OVERFILL.

19. Insert oil dipstick and/or attach fill cap.

20. Replace the front panel.

21. If the generator was not running due to a utility outage, simply press the AUTO button and close the lid. Be sure to dispose of the used oil and oil filter in accordance with national, state or local codes.

If the generator has been running because of an outage:

1. Reinstall the 7.5-amp fuse.

2. Verify the generator's main line circuit breaker is still OFF and press the AUTO button.

3. Allow the generator to crank, start and run to warm up for one to two minutes.

4. Turn the generator main line circuit breaker to the ON position.

5. Turn the utility main line circuit breaker to the ON position. The generator is now fully operational and powering the load.

6. Be sure to dispose of the used oil and oil filter in accordance with national, state or local codes.

 

Next generation series generators

If the generator has been running in an outage, refer to the "Shutting the Generator Off" section in How Do I Shut Down My Generator When It’s Powering My House (During an Outage)? Otherwise, proceed to step 1.

1. Unlock and lift lid and press the MANUAL button on control panel to start engine. Run unit for 3-5 minutes or until it is thoroughly warmed up. Press OFF button on control panel to shut down engine. 

2. Remove front panel when unit has cooled. Pull the blue oil drain hose free of retaining clip. Prepare a suitable container to drain the oil into, remove cap from oil drain hose and drain oil. 

3. Install the cap back on the oil drain hose. Position and secure oil drain hose with the retaining clip.

4. Remove oil filter by turning it counter-clockwise. 

5. Apply a light coating of clean engine oil to the gasket of the new filter. 

6. Screw new filter on by hand until gasket lightly contacts oil filter adapter. Then, tighten the oil filter an additional three-quarters to one full turn. Confirm it is tight and secure.

7. Fill the engine with the recommended amount of oil, referencing the table below:

 

Next Generation Series Power Rating	10 kW	14/18 kW	22–28 kW
Oil capacity including filter	Approx. 1.4 qt (1.3 L)	Approx. 2.5 qt (2.4 L)	Approx. 2.2 qt (2.1 L)

 

8. Press the MANUAL button on control panel to start engine. Run for one minute and inspect for leaks. 

9. Press the OFF button on control panel to stop engine. Wait five minutes. 

10. Inspect oil level. Add oil as needed. DO NOT OVERFILL.

11. Insert oil dipstick and/or attach fill cap.

12. Replace the front panel.

13.Press AUTO button on control panel. 

14.Close and lock lid.

15.Dispose of used oil and filter according to local, state, or national codes. 

 

If the generator has been running because of an outage:

1. Reinstall the 7.5-amp fuse.

2. Verify the generator's main line circuit breaker is still OFF and press the AUTO button.

3. Allow the generator to crank, start and run to warm up for one to two minutes.

4. Turn the generator main line circuit breaker to the ON position.

5. Turn the utility main line circuit breaker to the ON position. The generator is now fully operational and powering the load.

6. Be sure to dispose of the used oil and oil filter in accordance with national, state or local codes.