The Cummins/Onan B5.9 is a 5.9 L 6-cylinder turbocharged engine rated at 1800 rpm, producing up to 132 kW. It powers generator sets from Cummins/Onan, including the 6BTAA5.9-G5 CoolPac, 6BTAA5.9-G7, B5.9 engine and B5.9 series. It holds 16.4 L (4.3 gal) of oil and 19.75 L (5.2 gal) of coolant.
Also known as: Cummins B5.9
Part of the Cummins/Onan B5.9 engine family — 5 variants share parts & fitment.
| Oil capacity | 16.4 L |
|---|---|
| Coolant capacity | 19.75 L |
| Displacement | 5.9 L |
| Cylinders | 6 |
| Aspiration | turbocharged |
| Rated speed | 1800 rpm |
| Gross power | 132 kW |
| Part # | Description | Category |
|---|---|---|
| RU5045 | Air Cleaner | air_filter |
| 4988274 | Alternator | alternator |
| 3288689 | Belt | belt |
| V70509 | Lube Oil | fluid |
| FS1251/FF42000 | Fuel Filter | fuel_filter |
| LF3959 | Lube Filter | lube_filter |
| 12.001-3678-000 | Lubricating Oil Pressure Gauge | other_service |
| 13.001-3901-000 | Battery A/B Switch | other_service |
| 14.001-3912-000 | ON/OFF Switch (AUTO/MANUAL) | other_service |
| 3305062 | Heater, 240V | other_service |
| 3315032 | Heater, 120V | other_service |
| 3885910 | Red Paint, Spray can | other_service |
| 5.001-2674-000 | True Warning Light | other_service |
| 6.001-3789-000 | Low Oil Pressure Warning Light | other_service |
| 7.001-3890-000 | Circuit Breaker | other_service |
| 8210G003-12VDC | 3/4" 12V solenoid | other_service |
| 8210G3-24VDC | 3/4" 24V solenoid | other_service |
| 3971603 | Starter 12V | starter |
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 B5.9 engine has an oil capacity of 16.4 liters.
The Cummins/Onan B5.9 has a displacement of 5.9 liters with 6 cylinders.
The Cummins/Onan B5.9 powers 10 generator set(s), including Cummins/Onan 6BTAA5.9-G5 CoolPac, Cummins/Onan 6BTAA5.9-G7, Cummins/Onan B5.9 engine, Cummins/Onan B5.9 series, Cummins/Onan CFP59-F10.