The Cummins/Onan QSK50 series is a 50.3 L 16-cylinder 4-cycle industrial diesel engine rated at 1900 rpm, producing up to 1400 kW. It powers generator sets from Cummins/Onan, including the D-3519, D-3521, D-3523 and D-3524. It holds 204 L (53.9 gal) of oil and 161 L (42.5 gal) of coolant.
Also known as: Cummins QSK50 series
Part of the Cummins/Onan QSK50 engine family — 5 variants share parts & fitment.
| Oil capacity | 204.0 L |
|---|---|
| Coolant capacity | 161.0 L |
| Displacement | 50.3 L |
| Cylinders | 16 |
| Aspiration | 4-cycle industrial diesel |
| Rated speed | 1900 rpm |
| Gross power | 1400 kW |
How to read your Cummins/Onan engine serial & model number →
| Item | Spec | Capacity | Part # | Interval | |
|---|---|---|---|---|---|
| Air filter | — | ||||
| Fuel filter | Fleetguard® ES Filtration, CENTINEL™ | — | |||
| Oil filter | Fleetguard® ES Filtration, CENTINEL™ | — | |||
| Battery | — | ||||
| Belt | — | ||||
| Coolant | CENTINEL Advanced Engine Oil Management System | 4000.0 hours | — | ||
| Oil | Cummins Prelub System | 216.0 U.S. QT | — | ||
| 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. |
| 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. |
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 |
|---|---|---|
| 140-3230 | Cleaner, Air (Includes Elements - See Ref. No. 25 and 26) | air_filter |
| 140-3963 | Filter, Air | air_filter |
| 70781N | Element, Primary - Air Cleaner - Nelson - Heavy Duty | air_filter |
| 70782N | Element, Safety - Air Cleaner - Nelson - Heavy Duty | air_filter |
| AF25544 | Recommended air cleaner element - (heavy duty) primary element | air_filter |
| AF25545 | Recommended air cleaner element - (heavy duty) secondary element | air_filter |
| AF2559300 | Element, Replacement (Cummins Filtration Part Number) | air_filter |
| 149-2837 | Filter, Fuel | fuel_filter |
| 149-2853 | Filter, Fuel (Triplex Filter) | fuel_filter |
| A030M222 | Filter, Fuel (Triple Filter) | fuel_filter |
| MCBQSK0068 | Water Pump Gasket Set | gasket |
| 140-1260 | Fitting, Safety Filter | other_service |
| 140-1548 | Indicator, Service | other_service |
| M-2885786 | Cylinder Liner Kit | other_service |
| M-3007525 | Cylinder Liner Kit | other_service |
| M-3022157 | Cylinder Liner | other_service |
| 5394933 | Crankshaft Rear Oil Seal Removal & Installation Kit | seal |
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 QSK50 series engine has an oil capacity of 204.0 liters.
The Cummins/Onan QSK50 series has a displacement of 50.3 liters with 16 cylinders.
The Cummins/Onan QSK50 series powers 9 generator set(s), including Cummins/Onan D-3519, Cummins/Onan D-3521, Cummins/Onan D-3523, Cummins/Onan D-3524, Cummins/Onan DQGAA.