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Home›Engines›Cummins/Onan GTA28

Cummins/Onan GTA28 Engine

The Cummins/Onan GTA28 is a 28 L 6-cylinder turbocharged & aftercooled engine rated at 1500 rpm, producing up to 650 kW. It powers generator sets from Cummins/Onan, including the GFGA. It holds 5.5 L (1.5 gal) of oil and 45 L (11.9 gal) of coolant.

Also known as: Cummins GTA28

Part of the Cummins/Onan GTA28 engine family — 2 variants share parts & fitment.

28.0 L
Displacement
6
Cylinders
1500 rpm
Rated speed
650 kW
Gross power
On this pageSpecsGenerator setsMaintenanceFAQTorque & specsFluids

Engine specifications

Oil capacity5.5 L
Coolant capacity45.0 L
Displacement28.0 L
Cylinders6
AspirationTurbocharged & Aftercooled
Rated speed1500 rpm
Gross power650 kW

Maintenance schedule

ItemSpecCapacityPart #Interval
Air filterGas Supply Filter Pressure Rating—
Fuel filterStandard Carburetor – IMPCO Make—
Oil filterLube Oil Filter Types—
BatteryBattery Type—
BeltSingle-bearing alternators—
Coolant170.0—
Coolant filter—
OilMulti-viscosity or straight weight single viscosity NATURAL GAS ENGINE OIL that meets Mil-2104A(CB), Mil-2104B (CC), Mil-2104C (CD/SC), CE and CF-4 specification. Ash Content between .15 and .85 of one percent.29.7 gal—
Spark plugCranking Current—

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

Service specifications

7
TypeItemValueUnitCondition
PressureSAE J1349 test condition: barometric pressure29.61in. Hg100 kPa; 300 ft (91 m) altitude
PressureSAE J1349 test condition: water pressure0.30in. Hg1 kPa
TemperatureRating note (1): water temperature to aftercooler, or use of air-to-air aftercooler with 100 F or lower air temperature to the radiator32C (90 F)applies to 10.5:1 / 10:1 / 11:1 note-(1) ratings
TemperatureRating note (2): water temperature to aftercooler, or use of air-to-air aftercooler with 130 F or lower air temperature to the radiator54C (130 F)applies to 8.5:1 note-(2) ratings
TemperatureRating note (3): water temperature to aftercooler, or use of air-to-air aftercooler with 110 F or lower air temperature to the radiator32C (90 F)applies to 10.5:1 note-(3) ratings
TemperatureRating note (4): water temperature to aftercooler, or use of air-to-air aftercooler with 130 F or lower air temperature to the radiator54C (130 F)applies to 8.5:1 note-(4) ratings
TemperatureSAE J1349 test condition: inlet air temperature77F25 C

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
Fueldry processed natural gas905 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.

Common questions

What is the oil capacity of the Cummins/Onan GTA28?

The Cummins/Onan GTA28 engine has an oil capacity of 5.5 liters.

What is the displacement of the Cummins/Onan GTA28?

The Cummins/Onan GTA28 has a displacement of 28.0 liters with 6 cylinders.

Which generators use the Cummins/Onan GTA28 engine?

The Cummins/Onan GTA28 powers 1 generator set(s), including Cummins/Onan GFGA.