The Cummins/Onan NTA855-G is a 14 L 6-cylinder turbocharged engine rated at 1800 rpm, producing up to 298.4 kW. It powers generator sets from Cummins/Onan, including the DFM Series 50Hz and DFM Series 60Hz. It holds 40 L (10.6 gal) of oil and 55 L (14.5 gal) of coolant.
Also known as: Cummins NTA855-G
Part of the Cummins/Onan NTA855 engine family — 9 variants share parts & fitment.
| Oil capacity | 40.0 L |
|---|---|
| Coolant capacity | 55.0 L |
| Displacement | 14.0 L |
| Cylinders | 6 |
| Aspiration | Turbocharged |
| Rated speed | 1800 rpm |
| Gross power | 298 kW |
How to read your Cummins/Onan engine serial & model number →
Compiled from service & troubleshooting documentation across every generator set that uses the Cummins/Onan NTA855-G.
| Item | Spec | Capacity | Part # | Interval | |
|---|---|---|---|---|---|
| Air filter | — | 500 hr | |||
| Fuel filter | — | 500 hr | |||
| Oil filter | — | 500 hr | |||
| Belt | — | ||||
| Coolant | 55.0 liters | — | 2000 hr | ||
| Oil | ASTM D2 | 40.0 liters | — | 500 hr |
Pooled from every document that names this exact engine — confirm the interval and part number against your unit's serial number.
| Part # | Description | Category |
|---|---|---|
| 122-0526 | Bypass Hood, Air Inlet (Used on Heavy Duty Air Cleaner) | air_filter |
| 140-1346 | Air Cleaner (Includes Element) | air_filter |
| 140-2391 | Element - Air Cleaner (Standard) | air_filter |
| 140-2392 | Element, Air Cleaner - Primary | air_filter |
| 140-2393 | Element, Air Cleaner - Safety | air_filter |
| M-1398 | STANDARD AIR CLEANER | air_filter |
| M-1398-2 | HEAVY DUTY AIR CLEANER (OPTIONAL) | air_filter |
| M-1398-1 | DUCT | air_inlet |
| 511-0084 | Belt, Charging Alternator | belt |
| 511-0160 | Belt, Drive - V (Fan) | belt |
| 319-2236 | Bracket, Mounting | bracket |
| B-342-10 | CRANKCASE BREATHER | breather |
| 505-0019 | Bushing, Pipe - Reducer 1/2” to 3/8”, DFBF (1/2” to 3/8”) 505-0131 DFCB, DFCC, DFCE (3/4” to 3/8”) | bushing |
| 518-0548-58 | Clamp, Hose | clamp |
| 130-3537 | Filter, Water - W/Corosion Inhibiting Chemical DCA4 | coolant_filter |
| 130-3541 | Filter, Water - w/Corrosion Inhibiting Chemical DCA4 (Pre-Charging) | coolant_filter |
| CS-1075-1 | COOLANT FILTERS | coolant_filter |
| 0300-4623-09 | DFCB (600V) | current_transformer |
| 0300-4623-10 | DFCC (600V) | current_transformer |
| 0300-4623-24 | DFCB BR (0-480V) | current_transformer |
| 0300-4623-27 | DFCC BR (0-480V) | current_transformer |
| ES-1779-1 | VOLTAGE REGULATOR AND EXCITATION SWITCH | excitation_switch |
| CS-1130-1 | EXPANSION TANK CAP | expansion_tank_cap |
| M-1740 | SUPPLY LINE, FILTER TO INJECTION PUMP FS-1424 | fuel_pump |
| 155-2287-02 | Gasket, Flange (used with 155-2281 Elbow) | gasket |
| 501-0551 | Line, Fuel - Flexible (Bypass line) | hose |
| 503-1467-07 | Hose, Rubber (3/4" ID x 33" LG) Radiator to Filter Housing | hose |
| 503-1679-02 | Hose, Rubber - Upper | hose |
| 505-1414-01 | Hose, Rubber - Lower | hose |
| M-1739 | CYLINDER BLOCK RADIATOR DRAINCOCK AND OIL COOLER AND LOWER RADIATOR HOSE M-1739 | hose |
| 122-0755 | Lube & Bypass Filter (Latest Style Used In Engine Manufacturing) | oil_filter |
| LF3000 | Lube, Spin-On | oil_filter |
| M-1298 | CHECK OIL LEVEL (ON RIGHT SIDE OF ENGINE) | oil_filter |
| 100-1359 | Engine, Replacement (Cummins NTA855G) | other_service |
| 102-1335 | Plug, Oil Drain | other_service |
| 309-0437 | (222"F) | other_service |
| 504-0011 | Valve, Shutoff (1/2”) | other_service |
| 505-0100 | Nipple, Pipe - Close (1/2”) | other_service |
| 526-0219 | Washer, Flat (1/2) | other_service |
| 800-0048 | Screw, Cap - Hex Head (3/8-16 x 3/4”) | other_service |
| 850-0050 | Washer, Lock - Spring (3/8”) | other_service |
| 870-0212 | Nut, Locking (1/4-20) | other_service |
| 903-0124 | NA | other_service |
| 903-0204 | NA | other_service |
| 903-0500 | NA | other_service |
| 903-0604 | NA | other_service |
| 960-0138 | other_service | |
| 960-0606 | other_service | |
| S-1610 | VOLTAGE SELECTOR LIGHTS | other_service |
| 307-2621-02 | Relay, Start Solenoid (K4) | relay |
| 800-0092 | Screw, Cap - Hex Head (1/2-13 x 1.5) | screw |
| 151-0411 | Pickup, Magnetic | sensor |
| 193-0244 | Sender, Pressure - 0i1 | sensor |
| 193-0375 | # Sender, Water Temperature | sensor |
| 193-0432 | Sender, Oil Temperature (S2 Engine Block, E4 Oil Pan) | sensor |
| 309-0179 | 'Switch, Thermostatic - Hi Engine Coolant Temperature | sensor |
| 309-0269 | Switch, Low Engine Temperature (S4) | sensor |
| 333-0407 | Switch, Pressure - Oil, 14# PSI (SHUTDOWN) With Dual Terminals | sensor |
| 960-0504 | PCC Control Service Manual | service_manual |
| 960-0507 | Detector Control Service Manual | service_manual |
| 508-0292 | Washer, Sealing - Copper | washer |
| 526-0029 | *Washer, Flat (1/2") | washer |
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 NTA855-G engine has an oil capacity of 40.0 liters.
The Cummins/Onan NTA855-G has a displacement of 14.0 liters with 6 cylinders.
The Cummins/Onan NTA855-G powers 2 generator set(s), including Cummins/Onan DFM Series 50Hz, Cummins/Onan DFM Series 60Hz.
The Cummins/Onan NTA855-G oil change interval is every 500 hours.
A commonly reported issue on generators using the Cummins/Onan NTA855-G is: Overspeed shutdown.. Fix: Check governor and throttle linkages for freedom of movement. Check overspeed switch..