The Cummins/Onan QSK38 is a 37.8 L 12-cylinder 4-cycle industrial diesel engine rated at 1800 rpm, producing up to 940 kW. It powers generator sets from Cummins/Onan. It holds 186 L (49.1 gal) of oil and 112 L (29.6 gal) of coolant.
Also known as: Cummins QSK38
Part of the Cummins/Onan QSK38 engine family — 6 variants share parts & fitment.
| Oil capacity | 186.0 L |
|---|---|
| Coolant capacity | 112.0 L |
| Displacement | 37.8 L |
| Cylinders | 12 |
| Aspiration | 4-cycle industrial diesel |
| Rated speed | 1800 rpm |
| Gross power | 940 kW |
How to read your Cummins/Onan engine serial & model number →
| Item | Spec | Capacity | Part # | Interval | |
|---|---|---|---|---|---|
| Air filter | — | ||||
| Fuel filter | — | ||||
| Oil filter | — | ||||
| Battery | — | ||||
| Belt | — | ||||
| Coolant | — | ||||
| Oil | — | ||||
| Spark plug | — |
Pooled from every document that names this exact engine — confirm the interval and part number against your unit's serial number.
| Item | Action | Hours | Months | Notes |
|---|---|---|---|---|
| Lubricating oil | Test | 250 hr | 6 mo | First service — For high horsepower engines with Eliminator™ oil filter option: take oil samples every 250 hours and analyze per Cummins Engine Oil Recommendations Bulletin 3810340; repeat for at least three oil change intervals. |
| filters | Change | 1000 hr | with CENTINEL, depending on load factors | |
| ELIMINATOR self cleaning filter core | Other | 1500 hr | Requires servicing only every 1,500 hours. Saves up to 90% of lube system maintenance costs and increases productivity. | |
| fuel filter | Change | 1500 hr | Fleetguard NanoNet media | |
| engine oil | Change | 4500 hr | with CENTINEL, railway applications |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
| Fluid | Grade | Standard | Ambient | Capacity | Notes |
|---|---|---|---|---|---|
| Engine oil | Cummins Engine Oil Recommendations Bulletin 3810340 | Used to analyze oil samples for high horsepower engines with Eliminator™ oil filter option. | |||
| Fuel | B100 biodiesel | ASTM D6751 | Must conform prior to blending; revised to include a cold soak test; stability requirement still in effect. | ||
| Fuel | B20 biodiesel blend | ASTM D7467 | Applies to biodiesel blends B6–B20; includes oxidation stability requirement; replaces Cummins' previous EMA B20 specification requirement. Must be purchased from a BQ9000 Certified Marketer; B100 must be sourced from a BQ9000 Accredited Producer. | ||
| Fuel | B5 biodiesel | All Cummins automotive and industrial engines are compatible with B5 biodiesel. | |||
| Fuel | biodiesel (Europe) | EN 14214 | Published by CEN, European Committee for Standardization. Equivalent biodiesel specifications required internationally. |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
⚠ B20 has a solvent nature and may clean the vehicle fuel tank and lines.
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 |
|---|---|---|
| MCBQSK0068 | Water Pump Gasket Set | gasket |
| M-2885786 | Cylinder Liner Kit | other_service |
| M-3007525 | Cylinder Liner Kit | other_service |
| M-3022157 | Cylinder Liner | other_service |
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 QSK38 engine has an oil capacity of 186.0 liters.
The Cummins/Onan QSK38 has a displacement of 37.8 liters with 12 cylinders.
The Cummins/Onan QSK38 powers 1 generator set(s), including Cummins/Onan QSK38.