Air-cooled home standby generator oil capacity
Proper maintenance of your generator, including regular oil level checks, is essential for both reliability and efficiency. Always follow the manufacturer’s recommendations for oil type and service intervals, since running with low oil levels can cause serious damage. Both underfilling and overfilling the engine can harm performance and lead to costly repairs. For details on your generator’s oil capacity, see the information below or consult the specifications section of your owner’s manual. For help locating your manual, see: Where can I find a user manual or other documentation for my home standby generator?
Environment
This article applies to the following Generac generators:
- For Next Generation Series 10-28 kW air-cooled standby generators, see here.
- For Guardian Series 10-26 kW air-cooled standby generators (2017 to present), see here.
- For PowerPact Series 7.5 kW air-cooled standby generators, see here.
Note: For generators not listed above, including liquid-cooled models, oil capacity can be found in the product owner's manual or spec sheet on our product lookup page.
Basic steps for refilling generator oil
1. Start with less - Begin by adding oil slowly, starting with a smaller quantity than the maximum capacity.
2. Check regularly - After adding some oil, pause and to check the oil level using the dipstick. Wipe the dipstick clean, reinsert it fully, and then withdraw it to accurately check the oil level.
3. Add oil gradually - Continue to add oil in small increments, checking the dipstick after each addition. This method allows the oil to settle and provides a more accurate reading.
4. Avoid overfilling - It is critical to avoid overfilling the crankcase with oil. Overfilling can lead to increased pressure within the engine, which can cause leaks and damage to engine seals and other components.
5. Final check - Once the dipstick indicates the oil level is within the safe range, run the engine for a few minutes. This circulates the oil and allows for any air pockets to escape. Turn off the engine and let it rest for a few minutes before performing a final oil level check. Adjust if necessary.
Common models
Next Generation Series 10-28 kW
| Next Generation Series |
| Model | 10 kW | 14/18 kW | 22-28 kW |
| Number of cylinders | 1 | 2 | 2 |
| Displacement | 459 cc | 817 cc | 997 cc |
| 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) |
| Recommended oil filter | 070185ES |
Guardian Series 10-26 kW
| Guardian Series |
| Model | 10 kW | 14/18 kW | 20-26 kW |
| Number of cylinders | 1 | 2 | 2 |
| Displacement | 460 cc | 816 cc | 999 cc |
| 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) |
| Recommended oil filter | 070185ES |
PowerPact 7.5 kW
| PowerPact |
| Model | 7.5 kW |
| Engine type | GA-420 |
| Number of cylinders | 1 |
| Displacement | 25.6 in (420 cc) |
| Oil capacity, including filter | Approx. 1.2 qt (1.1 L) |
