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Cummins/Onan QSL9G5 Engine Engine

Name: Cummins/Onan QSL9G5 Engine
Brand: Cummins/Onan

The Cummins/Onan QSL9G5 is a 8.8 L 6-cylinder turbocharged engine rated at 1800 rpm. It powers generator sets from Cummins/Onan, including the BCC 330-50, C250 D2R, C275 D5 and C70. It holds 26.5 L (7.0 gal) of oil and 28.6 L (7.6 gal) of coolant.

Also known as: Cummins QSL9G5

8.8 L

Displacement

Cylinders

1800 rpm

Rated speed

26.5 L

Oil capacity

Engine specifications

Oil capacity	26.5 L
Coolant capacity	28.6 L
Displacement	8.8 L
Cylinders	6
Aspiration	Turbocharged
Rated speed	1800 rpm

Generator sets powered by this engine

Cummins/Onan BCC 330-50 Cummins/Onan C250 D2R Cummins/Onan C275 D5Cummins/Onan C70Cummins/Onan QSL9-G5

Common problems

Unknown J1939 Fault 251
Cause: Can be caused by battery disconnection/isolation without a run data save operation.
Flash-out of Fault Codes
Fix: 1. The diagnostic mode key switch must be in the On (I) position to flash out the fault codes. 2. In the diagnostic mode: a) With no active faults, the Warning and Stop lamps will be illuminated without flashing OR b) With active faults, the ECM will begin to flash out codes by first turning on the Warning lamp. 3. The Warning lamp will then turn off and the ECM will begin flashing the Stop lamp in sequence to represent the active fault code number. 4. As the fault code is flashed, short pauses will occur to indicate completion of each digit. The Warning lamp will illuminate to indicate the beginning of a fault code. 5. The ECM will continue to flash a fault until the operator uses the Fault increment (↑) or decrement (↓) rocker switch to change to a new fault.

Compiled from service & troubleshooting documentation across every generator set that uses the Cummins/Onan QSL9G5.

Maintenance schedule

Item	Capacity	Part #	Interval
Air filter		—	1000 hr	find
Fuel filter		—	500 hr	find
Oil filter		—	1000 hr	find
Belt		—	1000 hr	find
Coolant	28.6 L	—
Oil	26.5 L	—

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

Common questions

What is the oil capacity of the Cummins/Onan QSL9G5?

The Cummins/Onan QSL9G5 engine has an oil capacity of 26.5 liters.

What is the displacement of the Cummins/Onan QSL9G5?

The Cummins/Onan QSL9G5 has a displacement of 8.8 liters with 6 cylinders.

Which generators use the Cummins/Onan QSL9G5 engine?

The Cummins/Onan QSL9G5 powers 5 generator set(s), including Cummins/Onan BCC 330-50, Cummins/Onan C250 D2R, Cummins/Onan C275 D5, Cummins/Onan C70, Cummins/Onan QSL9-G5.

What is a common problem with the Cummins/Onan QSL9G5 engine?

A commonly reported issue on generators using the Cummins/Onan QSL9G5 is: Unknown J1939 Fault. Cause: Can be caused by battery disconnection/isolation without a run data save operation..