The Generac G9.0L G18 is a 8.9 L 8-cylinder naturally aspirated engine rated at 1800 rpm. It powers generator sets from Generac, including the MGG100M. It holds 8.5 L (2.2 gal) of oil and 20.8 L (5.5 gal) of coolant.
Also known as: Generac G9.0L G18
| Oil capacity | 8.5 L |
|---|---|
| Coolant capacity | 20.8 L |
| Displacement | 8.9 L |
| Cylinders | 8 |
| Aspiration | Naturally Aspirated |
| Rated speed | 1800 rpm |
Compiled from service & troubleshooting documentation across every generator set that uses the Generac G9.0L G18.
| Item | Spec | Capacity | Part # | Interval | |
|---|---|---|---|---|---|
| Oil | 62.8 L | — | 250 hr |
Pooled from every document that names this exact engine — confirm the interval and part number against your unit's serial number.
The Generac G9.0L G18 engine has an oil capacity of 8.5 liters.
The Generac G9.0L G18 has a displacement of 8.9 liters with 8 cylinders.
The Generac G9.0L G18 powers 1 generator set(s), including Generac MGG100M.
The Generac G9.0L G18 oil change interval is every 250 hours.
A commonly reported issue on generators using the Generac G9.0L G18 is: NG fuel system input pressure drops below 30 PSI (207 kPa) for a certain time frame. Cause: Low NG fuel pressure. Fix: The unit attempts to switch to the LPL fuel source. Almost immediately after the switch, a warning activates and the controller displays message FUEL PRESS Lo (Figure 15). The warning stops when NG input pressure rises to or above 30 PSI (207 kPa). Resetting the controller is unnecessary..