HomeEnginesCummins/Onan KT2300-G

Cummins/Onan KT2300-G Engine

The Cummins/Onan KT2300-G is a 37.7 L 12-cylinder engine rated at 1800 rpm, producing up to 679 kW. It powers generator sets from Cummins/Onan, including the 500 DFX-57R, 600 DFX-4R and 600 DFX-4XR. It holds 151.4 L (40.0 gal) of oil and 207.9 L (54.9 gal) of coolant.

Also known as: Cummins KT2300-G

37.7 L
Displacement
12
Cylinders
1800 rpm
Rated speed
679 kW
Gross power

Engine specifications

Oil capacity151.4 L
Coolant capacity207.9 L
Displacement37.7 L
Cylinders12
Rated speed1800 rpm
Gross power679 kW

Common problems

8
  • Weakness and Sleepiness
    Fix: Get out into fresh air immediately.
  • Vomiting
    Fix: Get out into fresh air immediately.
  • Muscular Twitching
    Fix: Get out into fresh air immediately.
  • 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.
  • Engine runs, shuts down, cranks for 75-seconds, cranking cycle stops, light ON.
    Fix: Check fuel supply.
  • Dizziness
    Fix: Get out into fresh air immediately.
  • "Low oil pressure shutdown."
    Fix: Check— 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.
  • "High engine temperature shutdown."
    Fix: Check— a. Coolant level. Replenish is necessary. b. City water cooled sets. Check water flow, valves, etc. c. Check sensor; check thermostat.

Compiled from service & troubleshooting documentation across every generator set that uses the Cummins/Onan KT2300-G.

Maintenance schedule

ItemSpecCapacityPart #Interval
Air filter
Fuel filterspin-off, throw-away unit200 hr
Oil filterspin-off throw away elements; replace at every oil change
Batteryspecific gravity 1.280 at 80F
Beltadjust to 1/2 inch depression between pulleys
Coolantcheck for rust or scale formation; flush if necessary207.9 litres
Coolant filterreplace periodically per General Maintenance section; compatible with plain water or ethylene glycol antifreeze; not compatible with stop-leak additives
Oil151.0 litres8 hr

Pooled from every document that names this exact engine — confirm the interval and part number against your unit's serial number.

Service intervals

17
ItemActionHoursMonthsNotes
Check Oil LevelCheck8 hrcheck approx. 15 min after shutdown; keep near FULL mark
Check Radiator CoolantCheck8 hr
Inspect SetInspect8 hr
Check Air CleanerCheck50 hr3 moclean if required; more often in dusty conditions
Check Cooling SystemCheck50 hr3 mocheck for rust or scale formation; flush if necessary
Clean and Inspect Crankcase BreatherClean50 hr
Inspect Fan BeltInspect50 hr3 moadjust to 1/2 inch depression between pulleys
Air Filter Cartridge - remove and shake out dirt, install new precleanerClean100 hrFRAM CA-250PL series
Change Crankcase OilChange100 hr3 mo
Clean and Inspect Battery Charging AlternatorInspect100 hr
Replace Oil Filter ElementReplace100 hr3 mo
Check all hardware, fittings, clamps, fasteners, exhaust system for securityCheck200 hr3 mowith set running, visually and audibly check exhaust system for leaks
Replace Fuel FilterReplace200 hr
Air Filter Cartridge - replace both precleaner and paper cartridgesReplace400 hrFRAM CA-250PL series
Generator Bearing InspectionInspect1000 hrinspect with unit running
Generator Bearing Replacement (prime power)Replace10000 hr24 mo
Generator Bearing Replacement (standby)Replace60 mo

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Service specifications

13
TypeItemValueUnitCondition
OtherAC frequency regulation0-3Hz Max.
PressureExternal prime pressure while cranking15psi (103 kPa)cranking for 15 seconds
PressureLow oil pressure shutdown14psi (96.53 kPa)
PressureMaximum permissible exhaust restriction (back pressure)3inches (76 mm) Hg
PressureMaximum return fuel line restriction4inches (100 mm) Hg
PressureNormal oil pressure50-70psi (345.0-483 kPa)immediately after start
PressureOil priming pressure30psi (207 kPa)priming procedure
SpeedOverspeed shutdown2100rpm
TemperatureCoolant operating temperature range165-195°F (73.9-90.6°C)
TemperatureHigh engine temperature shutdown205°F (96°C)
TorqueOil filter housing plug torque15 to 20lb-ft (20 to 27 N.m)
TorqueRotating rectifier diode torque30in. lb.or finger tight plus a quarter turn
VoltageAC voltage regulation±2%no load to full load, 0.8 PF

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Recommended fluids

FluidGradeStandardAmbientCapacityNotes
Coolantclean soft water with rust and scale inhibitor additive; ethylene glycol base antifreeze if freezing possible207.9 litres (55 gallons)do not use antifreeze with anti-leak/stop-leak additive if unit has coolant filter
Engine oil10Wbelow 23°C-10F (-23C) and below
Engine oilAPI Class CC/CD, max sulphated ash content 1.85%API151.0 litres (40 gallons)do not mix brands nor grades of oil
Engine oil307°C to 16°C20 to 60F (-7 to 16C)
Engine oil20-20W23°C to 1°C-10 to 30F (-23 to -1C)
FuelASTM No. 2 DieselASTM

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Procedures

5
Governor speed adjustment adjustment

⚠ Be prepared to assume manual control if adjustments are incorrect

Tools: screwdriver

  1. Remove four screws and cover from governor controller
  2. Disconnect wire from TB11-22 to disconnect starter solenoid
  3. Place Run-Stop-Remote switch to RUN; governor should stay at minimum fuel position
  4. Return switch to STOP and reconnect wire at TB11-22
  5. Position speed control rheostat to midrange (out 5 turns from low rpm)
  6. Adjust speed reference potentiometer counterclockwise four complete turns
  7. Start engine; adjust speed reference potentiometer clockwise/counterclockwise to reach correct rpm
  8. Adjust gain potentiometer clockwise then counterclockwise until stable and responsive
  9. Load and unload engine several times to confirm gain adjustment
  10. Shut down and restart engine to confirm no overspeed
  11. Replace governor control box cover
Generator support alignment to skid base installation

⚠ Generator support must be aligned to prevent premature bearing failure, vibration, drive disc failure

Tools: feeler gauge

  1. Set unit on mounting foundation with vibration isolators between skid base and foundation
  2. Secure skid base to isolators and isolators to foundation
  3. Remove two mounting bolts and use as jackscrews
  4. Raise generator and remove shims from between generator and support and skid base
  5. Adjust jackscrew tension and allow generator to hang free
  6. Measure clearance from skid base top to each generator support surface with feeler gauge
  7. Add 0.010 in (0.254mm) to each side to determine shim amount
  8. Turn jackscrews to allow clearance for placing shims
  9. Lower generator onto shims using jackscrews
  10. Recheck total clearance equals base-to-support clearance plus 0.010 in
  11. Remove jackscrews and reinstall as mounting bolts through support, shims, and skid base
  12. Secure and lock mounting bolts in place
Out-of-service protection (storage, up to six months) maintenance

⚠ For storage beyond six months refer to Cummins Service manual

Tools: tape

  1. Start and operate engine until thoroughly warm; disconnect fuel lines to filter and injector drain line
  2. Start engine on diesel fuel, then switch to preservative oil and run 5-10 minutes, stop engine and reconnect fuel lines
  3. Drain oil sump, fuel filters and fuel tank, reinstall drain plugs
  4. Disconnect electrical wiring, turn fuel pump shutoff valve fully counterclockwise, spray lubricating oil into intake manifold while cranking slowly
  5. Cover all openings with tape
  6. Drain coolant unless permanent antifreeze with rust inhibitor is used
  7. Store engine in dry, uniform temperature area
  8. Bar engine crankshaft two or three revolutions every three to four weeks
Preparing a stored engine for service maintenance

⚠ Do not smoke while servicing batteries - explosive gases emitted

  1. Clean accumulated dirt from exterior, remove covers, tape and wrappings
  2. Use suitable cleaner to remove rust preventive compound from unpainted surfaces
  3. Refill crankcase with clean lubricating oil; flush and fill cooling system
  4. Check coolant level, adjust or refill as necessary
  5. Connect batteries
  6. Verify no loads are connected to generator
  7. Perform prestart servicing and start engine
  8. Apply load to at least 50 percent of rated capacity
  9. Check all gauges read correctly
Priming the oil system maintenance

Tools: hand or motor-driven priming pump

  1. Remove oil inlet line from turbo-charger housing, fill bearing housing with clean oil, replace line, repeat for second turbo
  2. Fill crankcase to L (low) mark on dipstick
  3. Remove plug from head of oil filter housing and connect priming pump from clean lubricating oil source
  4. Prime until 30 psi (207 kPa) pressure is obtained
  5. Disconnect wire from fuel solenoid valve, close throttle, crank engine maintaining 15 psi (103 kPa) external prime for 15 seconds
  6. Remove external priming equipment, replace plug in filter housing, torque 15-20 lb-ft (20-27 N.m)
  7. Reconnect wire to fuel shut-off valve
  8. Complete oil fill to H (high) mark on dipstick

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Common questions

What is the oil capacity of the Cummins/Onan KT2300-G?

The Cummins/Onan KT2300-G engine has an oil capacity of 151.4 liters.

What is the displacement of the Cummins/Onan KT2300-G?

The Cummins/Onan KT2300-G has a displacement of 37.7 liters with 12 cylinders.

Which generators use the Cummins/Onan KT2300-G engine?

The Cummins/Onan KT2300-G powers 3 generator set(s), including Cummins/Onan 500 DFX-57R, Cummins/Onan 600 DFX-4R, Cummins/Onan 600 DFX-4XR.

How often should you change the oil in the Cummins/Onan KT2300-G?

The Cummins/Onan KT2300-G oil change interval is every 8 hours.

What is a common problem with the Cummins/Onan KT2300-G engine?

A commonly reported issue on generators using the Cummins/Onan KT2300-G is: Weakness and Sleepiness. Fix: Get out into fresh air immediately..