The Cummins/Onan GTA14 is a 14 L 6-cylinder turbocharged & aftercooled engine rated at 1800 rpm. It powers generator sets from Cummins/Onan, including the GTA14 qi 20 NA. It holds 41.7 L (11.0 gal) of oil and 19 L (5.0 gal) of coolant.
Also known as: Cummins Natural Gas Engines GTA14
Part of the Cummins/Onan GTA14 engine family — 3 variants share parts & fitment.
| Oil capacity | 41.7 L |
|---|---|
| Coolant capacity | 19.0 L |
| Displacement | 14.0 L |
| Cylinders | 6 |
| Aspiration | Turbocharged & Aftercooled |
| Rated speed | 1800 rpm |
How to read your Cummins/Onan engine serial & model number →
| Item | Spec | Capacity | Part # | Interval | |
|---|---|---|---|---|---|
| Air filter | — | 750 hr | |||
| Fuel filter | — | 750 hr | |||
| Oil filter | — | 750 hr | |||
| Battery | — | 1500 hr | |||
| Belt | — | 750 hr | |||
| Coolant | — | 6000 hr | |||
| Coolant filter | Fleetguard™ DCA4™ Water Filter Element. | — | 500 hr | ||
| Oil | 36.0 litres | — | 750 hr | ||
| Spark plug | — | 6000 hr |
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 |
|---|---|---|---|---|
| Other | Cold cranking amperes (CCA) - engine only (de-clutched load) | 900 | CCA | |
| Other | Reserve capacity - engine only (de-clutched load) | 320 | min. | |
| Pressure | Maximum allowable exhaust back pressure | 2 (50) | in. Hg. (mm Hg) | |
| Pressure | Maximum allowable intake air restriction with heavy duty air cleaner - clean element | 8 (203) | in. H2O (mm H2O) | clean element |
| Pressure | Maximum allowable intake air restriction with heavy duty air cleaner - dirty element | 15 (381) | in. H2O (mm H2O) | dirty element |
| Pressure | Maximum coolant friction head external to the engine | 5 (34) | PSI (kPa) | |
| Pressure | Maximum running pressure to carburetor (after regulation) | 6 (152) | in. H2O (mm H2O) | |
| Pressure | Maximum running pressure to engine mounted regulator | 20 (508) | in. H2O (mm H2O) | |
| Pressure | Minimum allowable pressure cap | 7 (48) | PSI (kPa) | |
| Pressure | Minimum running pressure to engine mounted regulator | 10 (254) | in. H2O (mm H2O) | |
| Pressure | Oil pressure at idle (minimum allowable) | 15 (103) | PSI (kPa) | idle |
| Pressure | Oil pressure at rated speed (minimum allowable) | 35 – 45 (241 – 310) | PSI (kPa) | rated speed |
| Resistance | Maximum allowable resistance of starting circuit | 002 | Ohms | |
| Speed | Low idle speed | 900 | RPM | |
| Speed | Maximum no-load governed speed | 1980 | RPM | |
| Speed | Maximum overspeed capability | 2100 | RPM | |
| Speed | Maximum rated speed | 1800 | RPM | |
| Speed | Minimum cranking speed | 150 | RPM | |
| Temperature | Maximum allowable oil temperature | 230 (110) | °F (°C) | |
| Temperature | Maximum allowable top tank temperature | 200 (93) | °F (°C) | |
| Temperature | Maximum turbine inlet temp (dry manifold) | 1300 (704) | °F (°C) | |
| Temperature | Minimum recommended top tank temperature | 160 (71) | °F (°C) | |
| Temperature | Standard thermostat (modulating) range | 175 – 195 (79 – 91) | °F (°C) | |
| Voltage | Minimum recommended battery capacity (cold soak 0° F / -18° C or above) | 24 | Volt |
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 | Multi-viscosity or straight weight single viscosity NATURAL GAS ENGINE OIL | Mil-2104A (CB), Mil-2104B (CC), Mil-2104C (CD/SC), CE and CF-4 | 41.7 litre | Total system capacity including by-pass filter 11 U.S. gal (41.7 L); oil pan capacity high/low 9.5 – 8.0 U.S. gal (36.0 – 30.3 L). Refer to CNGE Service Parts Topic SPT97-10. |
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 |
| LF750 | Bypass Filter, 750 in3 | bypass_filter |
| LF3000 | Lube, Spin-On | oil_filter |
| 3376592 | Inch Pound Torque Wrench | other_service |
| 7-19 | Spark PLUG | spark_plug |
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 GTA14 engine has an oil capacity of 41.7 liters.
The Cummins/Onan GTA14 has a displacement of 14.0 liters with 6 cylinders.
The Cummins/Onan GTA14 powers 1 generator set(s), including Cummins/Onan GTA14 qi 20 NA.
The Cummins/Onan GTA14 oil change interval is every 750 hours.