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Cummins/Onan NTA855-G Engine

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 — 17 variants share parts & fitment.

14.0 L

Displacement

Cylinders

1800 rpm

Rated speed

298 kW

Gross power

On this pageSpecs Generator sets Maintenance FAQ

Engine specifications

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

Generator sets powered by this engine

Cummins/Onan DFM Series 50Hz Cummins/Onan DFM Series 60Hz

How to read your Cummins/Onan engine serial & model number →

Common problems

High engine temperature shutdown
Cause: Coolant level
Fix: Check coolant level. Replenish if necessary.
Fault lamp lights and engine shuts down after running for a period
Cause: Oil level (engine will shut down if sensor is closed)
Fix: Check oil level.
Low oil pressure shutdown
Cause: Oil level
Fix: Check oil level. Replenish if necessary.
Overspeed shutdown. Overspeed shutdown
Fix: Check governor and throttle linkages for freedom of movement. Check overspeed switch.
Overspeed shutdown
Fix: Check governor and throttle linkages for freedom of movement; Check overspeed switch.
Overspeed light on, no shutdown. Overspeed light on, no shutdown
Fix: Disconnect wire at TB11-29. Light on after reset; replace engine monitor board.
Overspeed light on, no shutdown
Fix: Disconnect wire at TB11-29. Light on after reset; replace engine monitor board.
Overcrank fault lamp lights and engine stops cranking after approximately 75-seconds
Fix: See engine service manual for troubleshooting fuel system; After correcting fault, reset engine monitor relay by placing Run-Stop/Reset-Remote switch to Stop/Reset position, depressing Reset button, then to the required running position.
Low oil pressure shutdown. *Low oil pressure shutdown
Fix: A. Oil level. Replenish if necessary. b. Sensor. Faulty sensor will shut down engine. c. Refer to engine service manual for troubleshooting guide for oil system.
Low oil pressure light ON. No shutdown. *Low oil pressure light ON. No shutdown
Fix: Disconnect wire at TB11-30. Light ON after relay reset. Replace engine monitor board.
High engine temperature shutdown. *High engine temperature shutdown
Fix: A. Coolant level. Replenish if necessary. b. City water cooled sets. Check water flow, valves, etc. c. Check sensor; check thermostat. d. Radiator model, check fan belts, radiator for obstructions, etc.
High engine temperature light ON. No shutdown. *High engine temperature light ON. No shutdown
Fix: Disconnect wire at TB11-31. Light ON after relay reset. Replace engine monitor board.
Fault lamp lights, no fault exists
Fix: To check a no-fault condition, disconnect leads from TB11 terminals 29, 30 and 31. If fault lamp lights with leads disconnected, replace engine monitor board. Reconnect leads.
Fault lamp lights immediately after engine starts
Cause: Overspeed condition as engine starts
Fix: Check for overspeed condition as engine starts.
Engine stops cranking and fault lamp lights, after cranking approximately 75 seconds
Fix: See engine service manual for troubleshooting fuel system; After correcting problem, reset engine monitor relay by placing Run-Stop/Reset-Remote switch to Stop/Reset, then back to the required running position.

Compiled from service & troubleshooting documentation across every generator set that uses the Cummins/Onan NTA855-G.

Maintenance schedule

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.

Parts cataloged across the Cummins/Onan NTA855 family

Part #	Description	Category
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
511-0084	Belt, Charging Alternator	Belt
511-0160	Belt, Drive - V (Fan)	Belt
319-2236	Bracket, Mounting	Bracket
518-0548-58	Clamp, Hose	Clamp
130-3537	CE 1 130-3541 3318318 CE 1 4 501-0551 1 5 503-1467-07 1 503-0189 2 505-0022 1 502-0827	Coolant filter
130-3541	Filter, Water - w/Corrosion Inhibiting Chemical DCA4 (Pre-Charging)	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
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
122-0526	Element, Filter	Oil filter
122-0755	Lube & Bypass Filter (Latest Style Used In Engine Manufacturing)	Oil filter
LF3000	Lube, Spin-On	Oil filter
100-1359	Engine, Replacement (Cummins NTA855G)	Service part / kit
102-1335	Plug, Oil Drain	Service part / kit
305-0813-02	CUMMINS battery charger 208VAC/24VDC/10A	Service part / kit
307-2621-02	Relay, Start Solenoid (K4)	Service part / kit
309-0437	(222"F)	Service part / kit
504-0011	Valve, Shutoff (1/2”)	Service part / kit
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”)	Service part / kit
505-0100	Nipple, Pipe - Close (1/2”)	Service part / kit
526-0029	*Washer, Flat (1/2")	Service part / kit
526-0219	Washer, Flat (1/2)	Service part / kit
800-0048	Screw, Cap - Hex Head (3/8-16 x 3/4”)	Service part / kit
800-0092	Screw, Cap - Hex Head (1/2-13 x 1.5)	Service part / kit
850-0050	Washer, Lock - Spring (3/8”)	Service part / kit
870-0212	Nut, Locking (1/4-20)	Service part / kit
903-0124	NA	Service part / kit
903-0204	NA	Service part / kit
903-0500	NA	Service part / kit
903-0604	NA	Service part / kit
E204747	Coolant heater 240/480V 6420W 1PH	Service part / kit
508-0292	Washer, Sealing - Copper	Seal
151-0411	Pickup, Magnetic	Sensor
193-0244	Sender, Oil Pressure (E1)	Sensor
193-0375	Sender, Coolant	Sensor
193-0432	Sender, Oil Temperature (S2 Engine Block, E4 Oil Pan)	Sensor
309-0179	Switch, High Water Temperature (Standard Part) Side Mounted On Water Outlet Housing	Sensor
309-0269	Sender, Temperature-Lo Engine	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

Parts cataloged across all variants of this engine family — verify the exact part fits your specific variant and serial number before ordering.

Common questions

What is the oil capacity of the Cummins/Onan NTA855-G?

The Cummins/Onan NTA855-G engine has an oil capacity of 40.0 liters.

What is the displacement of the Cummins/Onan NTA855-G?

The Cummins/Onan NTA855-G has a displacement of 14.0 liters with 6 cylinders.

Which generators use the Cummins/Onan NTA855-G engine?

The Cummins/Onan NTA855-G powers 2 generator set(s), including Cummins/Onan DFM Series 50Hz, Cummins/Onan DFM Series 60Hz.

How often should you change the oil in the Cummins/Onan NTA855-G?

The Cummins/Onan NTA855-G oil change interval is every 500 hours.

What is a common problem with the Cummins/Onan NTA855-G engine?

A commonly reported issue on generators using the Cummins/Onan NTA855-G is: High engine temperature shutdown. Cause: Coolant level. Fix: Check coolant level. Replenish if necessary..