HomeEnginesCummins/Onan X2.5-G2

Cummins/Onan X2.5-G2 Engine

The Cummins/Onan X2.5-G2 is a 2.5 L 3-cylinder naturally aspirated engine rated at 1500 rpm, producing up to 27 kW. It powers generator sets from Cummins/Onan, including the X2.5. It holds 8 L (2.1 gal) of oil and 11 L (2.9 gal) of coolant.

Also known as: Cummins X2.5-G2

Part of the Cummins/Onan X2.5 engine family — 3 variants share parts & fitment.

2.5 L
Displacement
3
Cylinders
1500 rpm
Rated speed
27 kW
Gross power

Engine specifications

Oil capacity8.0 L
Coolant capacity11.0 L
Displacement2.5 L
Cylinders3
Aspirationnaturally aspirated
Rated speed1500 rpm
Gross power27 kW

Maintenance schedule

ItemSpecCapacityPart #Interval
Air filterHeavy Duty Dry replaceable element with restriction indicator
Fuel filterSpin-on fuel filters with water separator
Oil filterSpin-on full flow filter
Battery12-volt
Coolant50% ethylene glycol; 50% water11.0 l
Oil8.0 l

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

Service specifications

1
TypeItemValueUnitCondition
TemperatureLimiting ambient temp.** (°C)50°C** @ 13 mm H20

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
Coolant50% ethylene glycol; 50% water11.0 lJacket Water After cooled cooling system design

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 X2.5-G2?

The Cummins/Onan X2.5-G2 engine has an oil capacity of 8.0 liters.

What is the displacement of the Cummins/Onan X2.5-G2?

The Cummins/Onan X2.5-G2 has a displacement of 2.5 liters with 3 cylinders.

Which generators use the Cummins/Onan X2.5-G2 engine?

The Cummins/Onan X2.5-G2 powers 1 generator set(s), including Cummins/Onan X2.5.