How Do I Check the Oil Level in My Home Standby Generator?

Oil levels can be monitored by checking the level indicated on the dipstick, which is accessed by removing the front panel of the generator housing. Levels should be checked more often when the generator is run for extended periods.

  • Jan 26, 2026
  • Knowledge

Title
How Do I Check the Oil Level in My Home Standby Generator?
URL Name
How-Do-I-Check-the-Oil-Level-in-My-Home-Standby-Generator

Public Content

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. 

Checking the oil level

A home standby generator's oil level should be checked frequently, especially when running continuously during an outage. Maintaining appropriate oil levels ensures the generator's engine does not suffer engine damage.

Environment

These instructions apply to Guardian series home standby generators and the Next Generation Air-Cooled Standby Generator.

Sections

Checking the oil level on the Next Generation Air-Cooled Standby Generator

Follow the steps below to check the oil level:

  1. Set the utility MLCB to OFF (OPEN).
    Note: This is the first switch after the meter. For service entry-rated switches, this will be in the automatic transfer switch. For non-service-entry rated switches, this will be in the main circuit breaker for the home or in a standalone box.
  2. Unlock and lift the lid.
  3. Set the generator MLCB (generator disconnect) to OFF (OPEN).

  4. If the generator was running during the outage, allow it to cool down for approximately one minute before pressing OFF.
  5. Press the OFF button to shut down the generator. Wait five minutes before continuing.
  6. Remove the oil dipstick and wipe it dry with a clean cloth.
    22 kW - 28 kW dipstick location

    14 kW - 18 kW oil fill cap/dipstick location

    10 kW oil fill cap/dipstick location


  7. Completely insert the oil dipstick into the dipstick tube and remove it.
  8. Observe the oil level. It should be at the FULL mark on the dipstick.
  9. If needed, remove the oil fill cap and add the recommended oil until the oil level reaches the FULL mark. Reinsert the dipstick and install the fill cap. See: What type of oil should I use in my home backup generator?

To restart the generator

  1. Unlock and lift the lid.
  2. Press the AUTO button on the control panel.
  3. Allow the generator to start and warm up for a few minutes.
  4. Set the generator MLCB (generator disconnect) to ON (CLOSED).

The system is now operating in AUTO mode. The utility MLCB can be turned ON (CLOSED).

Checking the oil level on Guardian-series generators

Important: Verify the oil level daily when running the generator for extended periods during an outage. The generator will shut down if the oil level is low. If your generator is powering your house during an outage, it must be properly shut down before checking oil levels: How Do I Shut Down My Generator When It’s Powering My House (During an Outage)?
 

1. Set the utility main line circuit breaker switch (MLCB) to OFF (OPEN).
 
Note: This is the first switch after the meter. For service entry-rated switches, this will be in the automatic transfer switch. For non-service-entry rated switches, this will be in the main circuit breaker for the home or in a standalone box.

2. Set the generator MLCB (B) to OFF (OPEN).
 
image.png

3. IMPORTANT: If the generator was running during an outage: After flipping the breaker to remove loads from the generator, allow the generator to continue running without loads for a minimum of 5 minutes, then allow the generator to cool for an additional 5 minutes. Immediate shutdown after running under load can cause damage to engine components.
4. Press the red OFF button on the generator's control panel to turn the generator off. Wait five minutes. 
5. Remove the oil dipstick (F) and wipe it dry with a clean cloth. 

image.png

6. Completely insert the oil dipstick into oil the dip-stick tube and remove it.
 
Note: On generators featuring an 816cc engine (some 13 kW, 14 kW, 16 kW, and 18 kW models) the dipstick screws in. On these models, the dipstick should be screwed in fully when checking the oil level.

7. Observe the oil level. The oil level should be somewhere between the red marks in the image below, up to the FULL mark on the oil dipstick.
oil level.png

8. If the oil level is at or below the ADD indicator, remove the oil fill cap (pictured below) and add small amounts of oil to the engine (with the oil dipstick removed) until the oil level reaches the FULL mark.
 
IMG_0165-min (1).jpg 
 
Note: See the What Type of Oil Should I Use in My Home Backup Generator? article for information about choosing an appropriate oil.

9. Insert and fully secure the dipstick, and completely tighten the oil fill cap. IMPORTANT: An oil spill may occur If these elements are not secure.


To restart the generator: 

1. Press the AUTO button on the control panel. 
2. Allow the generator to start and warm up for a few minutes. 
3. Set the generator MLCB (generator disconnect) to ON (CLOSED).
4. Now that the system is operating in AUTO, the utility MLCB can be turned ON (CLOSED).
 

See also

 


 

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