The Cummins/Onan ISB 300* is a 5.9 L 6-cylinder engine rated at 2600 rpm, producing up to 224 kW. It powers generator sets from Cummins/Onan, including the ISB 300. It holds 15 L (4.0 gal) of oil and 9.9 L (2.6 gal) of coolant.
Also known as: Cummins ISB 300*
Part of the Cummins/Onan ISB engine family — 10 variants share parts & fitment.
| Oil capacity | 15.0 L |
|---|---|
| Coolant capacity | 9.9 L |
| Displacement | 5.9 L |
| Cylinders | 6 |
| Rated speed | 2600 rpm |
| Gross power | 224 kW |
How to read your Cummins/Onan engine serial & model number →
| Type | Item | Value | Unit | Condition |
|---|---|---|---|---|
| Other | Advertised horsepower | 300 | hp | |
| Other | Advertised horsepower | 315 | hp | |
| Other | Advertised horsepower | 330 | hp | |
| Other | Advertised horsepower | 350 | hp | |
| Other | Advertised horsepower | 370 | hp | |
| Other | Advertised horsepower | 400 | hp | |
| Other | Advertised horsepower | 450 | hp | |
| Other | Advertised horsepower | 500 | hp | |
| Other | Advertised horsepower | 525 | hp | |
| Other | Certification | 2001-CERTIFIED | ||
| Speed | Governed speed | 2000 | RPM | |
| Speed | Governed speed | 2100 | RPM | |
| Speed | Governed speed | 2200 | RPM | |
| Speed | Governed speed | 2600 | RPM | |
| Speed | Governed speed | 2800 | RPM | |
| Torque | Peak torque | 1050 | at 1400 RPM | |
| Torque | Peak torque | 1200 | at 1300 RPM | |
| Torque | Peak torque | 1450 | at 1300 RPM | |
| Torque | Peak torque | 1550 | at 1200 RPM | |
| Torque | Peak torque | 1650 | at 1200 RPM | |
| Torque | Peak torque | 600 | at 1600 RPM | |
| Torque | Peak torque | 660 | at 1600 RPM | |
| Torque | Peak torque | 950 | at 1400 RPM |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
| Part # | Description | Category |
|---|---|---|
| 55F8L059A | Freightliner Step-Van Applications, 175-205 HP, VP-44 Rotary Injection Pump | Fuel pump |
| 55F8L059B | Ford Truck, Freightliner Truck & Bus Applications, 175-225 HP, VP-44 Rotary Injection Pump | Fuel pump |
| 55F8L059C | Ford Truck, Freightliner Truck & Bus Applications, 230-275 HP, VP-44 Rotary Injection Pump | Fuel pump |
| 55F8L059D | Dodge Truck Applications, 215-235 HP, VP-44 Rotary Injection Pump | Fuel pump |
| 55G0L059D | Dodge Truck Applications, 235 HP, VP-44 Rotary Injection Pump, For applications without Crankshaft Speed Indicator Ring | Fuel pump |
| 55G0L059E | Dodge Truck Applications, 245 HP, VP-44 Rotary Injection Pump, For applications without Crankshaft Speed Indicator Ring | Fuel pump |
| P01-275 | Oil Filter | Oil filter |
| P01-300 | Oil Filter | Oil filter |
| 55F8D210SB | Complete Drop-In Engines, Build to Order, 175-225 HP, CAC, VP-44 Rotary Pump | Pump |
| 55F8D250SB | Complete Drop-In Engines, Build to Order, 230-275 HP, CAC, VP-44 Rotary Pump | Pump |
| 55F8D190H | Yard Tractor, 190 HP, CAC, HMRO Turbo, Front Sump, VP-44 Rotary Pump | Turbocharger |
| 55F8D250H | Yard Tractor, 250 HP, CAC, HMRO Turbo, Front Sump, VP-44 Rotary Pump | Turbocharger |
| 55G0D205H | Yard Tractor, 205 HP, CAC, HMRO Turbo, Front Sump, VP-44 Rotary Pump | Turbocharger |
| 55G0D225H | Yard Tractor, 225 HP, CAC, HMRO Turbo, Front Sump, VP-44 Rotary Pump | Turbocharger |
| 55G0D275G | Construction / Industrial, 275HP @ 2500 RPM, HMFO Turbo, Rear Pan, VP-44 Pump, 12 Volt | Turbocharger |
Parts cataloged across all variants of this engine family — verify the exact part fits your specific variant and serial number before ordering.
The Cummins/Onan ISB 300* engine has an oil capacity of 15.0 liters.
The Cummins/Onan ISB 300* has a displacement of 5.9 liters with 6 cylinders.
The Cummins/Onan ISB 300* powers 1 generator set(s), including Cummins/Onan ISB 300.