The Cummins/Onan GTA38 G1 is a 38 L engine rated at 1500 rpm, producing up to 744 kW. It powers generator sets from Cummins/Onan, including the GFJA.
Also known as: Cummins GTA38 G1
Part of the Cummins/Onan GTA38 engine family — 4 variants share parts & fitment.
| Displacement | 38.0 L |
|---|---|
| Rated speed | 1500 rpm |
| Gross power | 744 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.
| Type | Item | Value | Unit | Condition |
|---|---|---|---|---|
| Pressure | SAE J1349 test condition: barometric pressure | 29.61 | in. Hg | 100 kPa; 300 ft (91 m) altitude |
| Pressure | SAE J1349 test condition: water pressure | 0.30 | in. Hg | 1 kPa |
| Temperature | Rating note (1): water temperature to aftercooler, or use of air-to-air aftercooler with 100 F or lower air temperature to the radiator | 32 | C (90 F) | applies to 10.5:1 / 10:1 / 11:1 note-(1) ratings |
| Temperature | Rating note (2): water temperature to aftercooler, or use of air-to-air aftercooler with 130 F or lower air temperature to the radiator | 54 | C (130 F) | applies to 8.5:1 note-(2) ratings |
| Temperature | Rating note (3): water temperature to aftercooler, or use of air-to-air aftercooler with 110 F or lower air temperature to the radiator | 32 | C (90 F) | applies to 10.5:1 note-(3) ratings |
| Temperature | Rating note (4): water temperature to aftercooler, or use of air-to-air aftercooler with 130 F or lower air temperature to the radiator | 54 | C (130 F) | applies to 8.5:1 note-(4) ratings |
| Temperature | SAE J1349 test condition: inlet air temperature | 77 | F | 25 C |
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 |
|---|---|---|---|---|---|
| Fuel | dry processed natural gas | 905 BTU per standard cubic foot (33.72 kJ/l) lower heating value, used for the tabulated ratings; deration may be required due to altitude, temperature, type of fuel or use of a catalytic converter |
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 |
|---|---|---|
| 3822524 | Use on v-belts ( 3/8 to 7/8) and v-ribbed belts with 5 ribs or less. | Belt |
| 3822525 | Use on v-beits larger than 7/8 in. and v-ribbed belts with 6 or more ribs. | Belt |
| 3305373 | Cummins Part No. DCA4 Units | Coolant filter |
| 3315459 | Cummins Part No. DCA4 Units | Coolant filter |
| 3317428 | Cummins Part No. DCA4 Units | Coolant filter |
| 3318320 | DCA4 Powder DCA95 (20 units) | Coolant filter |
| DCA95 | Coolant Filter | Coolant filter |
| 3376891 | Flourescent Tracer Add to oil. Use with blacklight to find oil leaks | Fluid |
| 3375049 | Oil Filter Wrench | Oil filter |
| 3096680 | Piston STC 13.8:1 Ratio | Service part / kit |
| 3096681 | Piston KT Series 15.5:1 Ratio | Service part / kit |
| 3096682 | Piston KTA Series 14.5:1 Ratio | Service part / kit |
| 3096683 | Piston 13.5:1 Ratio | Service part / kit |
| 3096684 | Piston KTA 15.7:1 Ratio | Service part / kit |
| 3096685 | Piston STC 13.9:1 Ratio | Service part / kit |
| 3375432 | Crack Detection Kit | Service part / kit |
| 3375434 | Crack Detection Developer | Service part / kit |
| 3377253 | Blacklight (AC) Inspect for oil leak | Service part / kit |
| 3377394 | Blacklight (DC) Inspect for oil leak | Service part / kit |
| 3377462 | Optical Tachometer | Service part / kit |
| 3377464 | Reflective Tape | Service part / kit |
| 3628731 | Piston STC Kit | Service part / kit |
| 3630913 | Piston KTA-50-G7 | Service part / kit |
| 3631241 | Piston Kit STC 13.9:1 Ratio | Service part / kit |
| 3631242 | Piston Kit 13.5:1 Ratio | Service part / kit |
| 3631243 | Piston Kit KTA 15.7:1 Ratio | Service part / kit |
| 3631244 | Piston Kit KTA Series 14.5:1 Ratio | Service part / kit |
| 3631245 | Piston Kit KT Series 15.5:1 Ratio | Service part / kit |
| 3631246 | Piston Kit STC 13.8:1 Ratio | Service part / kit |
| 3803530 | Piston Assembly STC | Service part / kit |
| 3804747 | Piston Kit KTA-50-G7 | Service part / kit |
| 3804885 | Piston KTA-50-G8/G9 | Service part / kit |
| 4089847 | Piston Kit GTA38/19 | Service part / kit |
| 4090013 | Piston Kit KTA-38-M2 | Service part / kit |
| 4090029 | Piston Kit QSK19CE | Service part / kit |
| 4090181 | Piston GTA38/19 | Service part / kit |
| 4097889 | Piston KTA-38-M2 | Service part / kit |
| 4910463 | Piston QSK19R/M | Service part / kit |
| 4910465 | Piston QSK Series | Service part / kit |
| 4916177 | Piston GTA/GQSK19 | Service part / kit |
| 4918058 | Piston QSK19CE | Service part / kit |
| 4922319 | Piston QSK19C | Service part / kit |
| 4955233 | Piston Kit QSK19R/M | Service part / kit |
| 4955235 | Piston Kit QSK Series | Service part / kit |
| 4955236 | Piston Kit QSK19C | Service part / kit |
| 4955238 | Piston Kit GTA/GQSK19 | Service part / kit |
| M-205091 | Valve Lock | Service part / kit |
| M-2881944 | Kit - Exhaust Valve | Service part / kit |
| M-4955238 | Piston Kit | Service part / kit |
| 3376898 | Engine Water Pump | Pump |
| 3375411 | Thermostat Seal Mandrel | Thermostat |
| 3375055 | Pressure Regulator Removal Tool | Tool |
| 3375182 | Valve Spring Tester | Tool |
| 3375301 | Tube Cutter | Tool |
| 3376579 | Open spin-on full flow filter for inspection | Tool |
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 GTA38 G1 has a displacement of 38.0 liters.
The Cummins/Onan GTA38 G1 powers 1 generator set(s), including Cummins/Onan GFJA.