Cummins/Onan QST30 — Specs, Engine, Parts & Maintenance

Service parts for the QST30

Grouped by system, with how many of each the parts manual calls for.

Oil system

1 required

Belts

1 required

Prices captured from merchant listings; some links are affiliate links. Confirm against your serial number before ordering.

Specifications

Standby power	895 kW
Standby kVA	1200
Prime power	806 kW
Oil capacity	154.0 L
Alternator	35 amps
Voltage options	50 V, 60 V
Coolant capacity	114.0 L
Max ambient	51.0 °C
Dimensions (L×W×H)	3092×1448×1828 mm
Dry weight	3565 kg

Maintenance & consumables

Item	Spec	Capacity	Part #	Interval
Oil filter	Oil filter wrench		3375049		Amazon eBay
Belt	water pump type grease listed below, or its equivalent		ST669		Amazon eBay $204.59

Service intervals

Item	Action	Hours	Months	Notes
Coolant filter	Replace	250 hr	6 mo	Change service coolant filter at every oil and filter change interval
Cooling fan	Check	250 hr	6 mo	Check for cracks, loose rivets, bent or loose blades
Crankcase breather tube	Clean	250 hr	6 mo	Check internally for obstructions or sludge
Drive belts	Check	250 hr	6 mo	Replace if cracked or frayed
Fan drive idler pivot arm assembly	Lubricate	250 hr	6 mo	Lubricate until grease appears from under the cap
Fuel filter (spin-on)	Replace	250 hr	6 mo	Whichever comes first
Fuel lift pump inlet screen / prefilter	Clean	250 hr	6 mo	Clean with compressed air or replace
Lubricating oil	Test	250 hr	6 mo	First service — For high horsepower engines with Eliminator™ oil filter option: take oil samples every 250 hours and analyze per Cummins Engine Oil Recommendations Bulletin 3810340; repeat for at least three oil change intervals.
Lubricating oil and filters	Change	250 hr	6 mo	Whichever comes first; generator drives 250 hours or 12 months
Supplemental coolant additive (SCA) concentration	Test	250 hr	6 mo	Test whenever coolant is added between filter changes
filters	Change	1000 hr		with CENTINEL, depending on load factors
ELIMINATOR self cleaning filter core	Other	1500 hr		Requires servicing only every 1,500 hours. Saves up to 90% of lube system maintenance costs and increases productivity.
fuel filter	Change	1500 hr		Fleetguard NanoNet media
Batteries	Check	2000 hr	12 mo	Check electrolyte level and state of charge
Coolant heater	Check	2000 hr	12 mo	Check for loose connections, frayed wires, coolant leaks
Cooling fan drive belt (front idler)	Adjust	2000 hr	12 mo	No adjustment required for shock absorber equipped engines
Crankshaft end clearance	Test	2000 hr	12 mo	Measure with dial indicator
Engine mounts	Check	2000 hr	12 mo	Check torque on nuts and bolts; inspect rubber
Engine oil heater	Check	2000 hr	12 mo	Oil pan should be warm; inspect connections and wires
Engine steam cleaning	Clean	2000 hr	12 mo	Cover all engine openings and electrical equipment
Hoses (bypass oil filter and cooling system)	Inspect	2000 hr	12 mo	Replace as necessary
Overhead set (crossheads and valves)	Adjust	2000 hr	12 mo	Initial adjustment at 2000 hours; do not adjust again before 6000 hours or 2 years
engine oil	Change	4500 hr		with CENTINEL, railway applications
Air compressor carbon buildup	Clean	6000 hr	24 mo	Complete air compressor inspection required
Air compressor unloader and valve assembly	Clean	6000 hr	24 mo	Clean with solvent and non-metallic brush
Coolant thermostat housing	Replace	6000 hr	24 mo	Remove and install procedure given
Coolant thermostat seal	Replace	6000 hr	24 mo	Install seal lip up, no more than 0.57 mm below cast edge
Coolant thermostats	Replace	6000 hr	24 mo	Inspect for reuse; discard if barrel worn or fretted
Cooling system (flush and change coolant)	Change	6000 hr	24 mo	Whichever comes first
Fan drive idler pulley assembly	Inspect	6000 hr	24 mo	Rebuild or replace as necessary
Fan hub, belt driven	Inspect	6000 hr	24 mo	Inspect for proper end clearance and grease leakage
Turbocharger	Inspect	6000 hr	24 mo	Check blades, shaft rotation, axial and radial clearance
Vibration damper	Inspect	6000 hr	24 mo	Must be replaced after 24,000 hours regardless of measurement
Water pump	Replace	6000 hr	24 mo	Rebuild or replace; minor weep hole streaking before 6000 hours is normal
Rupture basin leak detect switch	Test		12 mo	In some areas, weekly inspections may be required by safety code regulations.

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

Type	Item	Value	Unit	Condition
Clearance	Actuator maximum range	0 - 21	mm
Clearance	Actuator position fault threshold	1.5	mm	more than commanded position
Clearance	Compressor impeller radial clearance (HX60) (max)	0.46	mm [0.018 in]
Clearance	Compressor impeller radial clearance (HX60) (min)	0.15	mm [0.006 in]
Clearance	Crankshaft end clearance (max)	0.32	mm [0.013 in]
Clearance	Crankshaft end clearance (min)	0.14	mm [0.006 in]
Clearance	Fan hub bearing end clearance (max)	0.15	mm [0.006 in]
Clearance	Fan hub bearing end clearance (min)	0.03	mm [0.001 in]
Clearance	Turbine wheel radial clearance (HX60) (max)	0.53	mm [0.021 in]
Clearance	Turbine wheel radial clearance (HX60) (min)	0.20	mm [0.008 in]
Clearance	Turbocharger (Holset HX60) shaft end clearance (max)	0.10	mm [0.004 in]
Clearance	Turbocharger (Holset HX60) shaft end clearance (min)	0.03	mm [0.001 in]
Other	Air compressor discharge line carbon deposit (max)	2	mm [1/16 in]
Other	All continuity checks - OK (no open circuit) if	less than 10	ohms	continuity check
Other	Bearing grease quantity	81	ml
Other	Compression ratio	14.7:1
Other	DB9F-DB9M serial cable length (Part Number 4918418)	1.83	M
Other	ESS circuits shorts to ground - OK (no short circuits) if	more than 10	kohms	shorts to ground
Other	Extension DB9F to DB9M length (Part Number 3162851)	30.48	M
Other	Frequency regulation	Isochronous
Other	Governor duty cycle range	25 - 93	%
Other	Governor regulation class	ISO 8528 Part 1 Class G3
Other	INLINE™5 datalink adapter current requirement	250	mA	at +8 VDC to +50 VDC
Other	Magnetic Pickup proximity to gear teeth	0.71 - 1.07	mm	Approx. 1/2 to 3/4 turn
Other	Maximum intake restriction with heavy duty air cleaner, clean filter element	305	mm H2O [12 in H2O]
Other	Maximum intake restriction with heavy duty air cleaner, dirty filter element	635	mm H2O [25 in H2O]
Other	Rack test position range	0 to 19	mm
Other	Start delay adjustment range	0 to 300	seconds
Other	Stop delay adjustment range	0 to 600	seconds
Other	Torque adjustment range	0% to +1%	% duty cycle
Other	USB cable length (Part Number 4918419)	2	M
Other	USB cable length (Part Number 4918591)	5	M
Other	Vibration damper thickness	80	mm [3.150 in]
Other	Voltage regulator PWM duty cycle range	0 - 60	%
Other	Wrist strap resistance	approximately 1	megohm
Pressure	Engine oil pressure - idle	20	psi	idle mode
Pressure	Engine oil pressure - normal	45-65	psi	run mode
Pressure	Exhaust back pressure, maximum	75	mm Hg [3 in Hg]	at rated speed and load
Pressure	Max Back Pressure	41.0	in. H2O (10.2 kPa)
Pressure	Max. Static Restriction	0.50	in H2O (124.50 Pa)
Pressure	Maximum Air Cleaner Restriction	25.0	in. H2O (6.2 kPa)
Pressure	Maximum Coolant Friction Head	10.0	psi (68.9 kPa)
Pressure	Maximum Coolant Static Head	46.0	ft (14.0 m)
Pressure	Maximum Inlet Restriction	4.0	in. Hg (101.6 mm Hg)
Pressure	Maximum Return Restriction	10.0	in. Hg (254.0 mm Hg)
Pressure	Maximum air cleaner restriction	6.2	kPa
Pressure	Maximum allowable restriction to fuel pump, clean filter	64	mm Hg [2.5 in Hg]
Pressure	Maximum allowable restriction to fuel pump, dirty filter	100	mm Hg [4.0 in Hg]
Pressure	Maximum allowable return line restriction	63	mm Hg [2.5 in Hg]
Pressure	Maximum cooling air flow static restriction	0.12	kPa
Pressure	Maximum exhaust back pressure	6.8	kPa
Pressure	Maximum fuel inlet restriction	27	kPa
Pressure	Maximum fuel return line restriction	67.5	kPa
Pressure	Minimum pressure cap	48	kPa [7 psi]
Pressure	Oil pressure shutdown limit - idle mode	10	psi
Pressure	Oil pressure shutdown limit - run mode	35	psi
Pressure	Oil pressure warning limit - idle mode	15	psi
Pressure	Oil pressure warning limit - run mode	40	psi
Pressure	Oil pressure, main oil rifle, maximum at rated rpm (15W40 oil at 107 C [225 F])	448	kPa [65 psi]	at rated rpm
Pressure	Oil pressure, main oil rifle, minimum at idle rpm	98	kPa [14 psi]	at idle rpm

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

Fluid	Grade	Standard	Ambient	Capacity	Notes
Coolant	50/50 ethylene glycol antifreeze and water (40 to 60% working range)	TMC RP 329 (ethylene glycol) or TMC RP 330 (propylene glycol)	above -36°C	85.0 L	50/50 mixture gives -36 C [-34 F] freeze point and 110 C [228 F] boiling point. Use Fleetguard Compleat. Engine only capacity 85 liters [22.4 U.S. gal].
Engine oil		Cummins Engine Oil Recommendations Bulletin 3810340			Used to analyze oil samples for high horsepower engines with Eliminator™ oil filter option.
Engine oil	15W-40 (multigrade)	API CF-4, CG-4, CF-4/SG, or CG-4/SH		76.0 L	Nominal ash content 1 to 1.5 percent mass. 132 L [35 U.S. gal] oil pan option. Special break-in oils not recommended.
Fuel	ASTM No. 2D diesel				No. 1D acceptable below 0 C [32 F] blended with No. 2D. Viscosity must be kept above 1.3 cSt at 40 C [104 F].
Fuel	B100 biodiesel	ASTM D6751			Must conform prior to blending; revised to include a cold soak test; stability requirement still in effect.
Fuel	B20 biodiesel blend	ASTM D7467			Applies to biodiesel blends B6–B20; includes oxidation stability requirement; replaces Cummins' previous EMA B20 specification requirement. Must be purchased from a BQ9000 Certified Marketer; B100 must be sourced from a BQ9000 Accredited Producer.
Fuel	B5 biodiesel				All Cummins automotive and industrial engines are compatible with B5 biodiesel.
Fuel	No. 2 diesel				Direct injection fuel system
Fuel	Number 2 diesel fuel				Direct injection fuel system
Fuel	biodiesel (Europe)	EN 14214			Published by CEN, European Committee for Standardization. Equivalent biodiesel specifications required internationally.
Fuel	number 2 diesel fuel				Direct injection
Other	DCA4 supplemental coolant additive				Recommended concentration 1.5 units per 3.8 liters [1 U.S. gal]; never below 1.2 or above 3 units. Reduce DCA4 by one-third if Methoxy Propanol antifreeze is used.

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

Fault codes

Code	Name	Meaning	Severity	Action
101	IDLE MODE	Indicates that the engine is operating in idle mode.	Warning	When engine idle function enabled, control automatically sets lower oil pressure warning and shutdown trip points.
102	EMERGENCY STOP	Indicates local or remote Emergency Stop.	Shutdown	Turn switch clockwise and allow it to pop out (local only). Move Run/Off/Auto switch to Off. Press Reset switch. Select Run or Auto.
111	Engine Control Module - Critical internal failure.	Engine will not start.	Shutdown	Engine will not start.
115	No engine speed signal detected	No engine speed signal detected between pins 21 and 22 of Engine Harness Connector.	Shutdown	Engine is shut down and cannot be run. Common Alarm output is energized.
121	Engine Speed/Position Sensor Circuit - Lost one of two signals from the magnetic pickup sensor.	No action is taken by the ECM.	Warning	No action is taken by the ECM.
1211	Fuel Shutoff Valve #1 Circuit - Root cause not known (left bank).	Engine will shut down.	Shutdown	Engine will shut down.
1212	Fuel Shutoff Valve #2 Circuit - Root cause not known (right bank).	Engine will shut down.	Shutdown	Engine will shut down.
122	Intake Manifold Pressure Sensor #1 Circuit - Shorted high (left bank).	No action is taken by the ECM. Possible loss of performance.	Warning	No action is taken by the ECM. Possible loss of performance.
123	Intake Manifold Pressure Sensor #1 circuit - Shorted low (left bank).	No action is taken by the ECM. Possible loss of performance.	Warning	No action is taken by the ECM. Possible loss of performance.
128	Intake Manifold Pressure Sensor #2 circuit - Shorted high (right bank).	No action is taken by the ECM. Possible loss of performance.	Warning	No action is taken by the ECM. Possible loss of performance.
129	Intake Manifold Pressure Sensor #2 Circuit - Shorted low (right bank).	No action is taken by the ECM. Possible loss of performance.	Warning	No action is taken by the ECM. Possible loss of performance.
135	High voltage at engine oil pressure sensor signal	No engine protection for oil pressure.	Warning	No engine protection for oil pressure.
141	Low voltage at engine oil pressure sensor signal	No engine protection for oil pressure.	Warning	No engine protection for oil pressure.
1411	Generator Output Frequency Potentiometer - Shorted high.	The frequency adjustment feature will be disabled and a default value of zero will be used. Possible loss of performance.	Warning	The frequency adjustment feature will be disabled and a default value of zero will be used. Possible loss of performance.
1412	Droop Adjust Potentiometer - Shorted high.	The droop adjustment feature will be disabled and a default value of zero will be used. Possible loss of performance.	Warning	The droop adjustment feature will be disabled and a default value of zero will be used. Possible loss of performance.
1413	Controller Configuration Error.	Engine will not start.	Shutdown	Engine will not start.
1416	Fail to Shutdown.	The operator has enabled the user-engaged engine shutdown override feature. No engine protection features are working.	Warning	No engine protection features are working.
1417	Controller will not Powerdown.	The ECM can not power down from some unknown condition. Possible drain on battery.	Warning	Possible drain on battery.
1418	Gain Adjust Potentiometer - Shorted high.	The gain adjustment feature will be disabled and a default value of zero will be used. Possible loss of performance.	Warning	The gain adjustment feature will be disabled and a default value of zero will be used. Possible loss of performance.
1424	Relay High Side Driver Diagnostic has detected an error.	The user interface panel lamps will not function correctly. No action is taken by the ECM.	Warning	No action is taken by the ECM.
1425	Common Shutdown Relay Driver Diagnostic has detected an error.	The shutdown panel lamp will not function correctly. No action is taken by the ECM.	Warning	No action is taken by the ECM.
1426	Common Warning Relay Driver Diagnostic has detected an error.	The warning panel lamp will not function correctly. No action taken by the ECM.	Warning	No action taken by the ECM.
1427	Overspeed (OS) Relay Driver Diagnostic has detected an error.	The overspeed panel lamp will not function correctly. No action taken by the ECM.	Warning	No action taken by the ECM.
1428	Low Oil Pressure (LOP) Relay Driver Diagnostic has detected an error.	The low oil pressure lamp will not function correctly. No action is taken by the ECM.	Warning	No action is taken by the ECM.
1429	High Engine Temperature (HET) Relay Driver Diagnostic has detected an error.	The high engine temperature panel lamp will not function correctly. No action is taken by the ECM.	Warning	No action is taken by the ECM.
143	Low oil pressure warning	Voltage signal indicates oil pressure has dropped below the warning threshold for low oil pressure. Calibration-dependent engine shut down occurs, or no action taken by ECM. Pre-Low oil pressure relay driver is energized.	Warning	No effect on performance. Common Warning output is energized. Pre-low Oil Pressure relay driver is energized.
1431	Pre-Low Oil Pressure Relay Driver diagnostic has detected an error.	The Pre-Low oil pressure panel lamp will not function correctly. No action is taken by the ECM.	Warning	No action is taken by the ECM.
1432	Pre-High Engine Temperature Relay Driver Diagnostic has detected an error.	The Pre-High engine temperature panel lamp will not function correctly. No action is taken by the ECM.	Warning	No action is taken by the ECM.
1433	Operator interface Mode Transition to Emergency Stop (due to E-Stop).	Engine will shut down and will not restart until the emergency stop switch has been reset.	Shutdown	Engine will shut down and will not restart until the emergency stop switch has been reset.
1434	Operator Interface Mode Transition to Emergency Stop (due to remote E-Stop).	Engine will shut down and will not restart until the remote emergency stop switch has been reset.	Shutdown	Engine will shut down and will not restart until the remote emergency stop switch has been reset.
1435	Engine Cold - Potential starting problem.	No action is taken by the ECM. Possible hard starting.	Warning	No action is taken by the ECM. Possible hard starting.
1438	Fail to Crank.	No action is taken by the ECM, although the engine will not start.	Warning	No action is taken by the ECM, although the engine will not start.
144	High voltage at engine coolant temperature sensor signal	No engine protection for coolant temperature. Possible white smoke.	Warning	No engine protection for coolant temperature. Possible white smoke.
1443	Battery #1 Voltage Low - Critical.	Battery is dead. Engine will not start.	Shutdown	Engine will not start.
145	Low voltage at engine coolant temperature sensor signal	No engine protection for coolant temperature. Possible white smoke.	Warning	No engine protection for coolant temperature. Possible white smoke.
146	High coolant temperature warning	Voltage signal indicates coolant temperature has exceeded above the warning threshold for high coolant temperature. Calibration-dependent engine shut down occurs, or no action is taken by ECM. Pre-High engine temperature relay driver is energized.	Warning	No effect on performance. Common Warning output is energized. Pre-High Coolant Temperature relay driver is energized.
1473	The ECM Watchdog has failed.	Engine will shutdown.	Shutdown	Engine will shutdown.
1479	Fail to Start Relay Driver Diagnostic has detected an error.	The fail to start panel lamp will not function correctly. No action is taken by the ECM.	Warning	No action is taken by the ECM.
151	High coolant temperature shutdown	Voltage signal indicates coolant temperature has exceeded the shutdown threshold for high coolant temperature. Engine will shut down. High engine temperature relay driver is energized.	Shutdown	Engine will shut down. High engine temperature relay driver is energized.
152	Engine Coolant Temperature Low - Warning.	Voltage signal indicates coolant temperature has dropped below the warning threshold for low coolant temperature. No action is taken by ECM. Possible hard starting.	Warning	No action is taken by ECM. Possible hard starting.
153	Intake Manifold Temperature Sensor #1 Circuit - Shorted high (left bank).	No engine protection for intake manifold temperature. Possible smoke at engine start-up and no-load operation.	Warning	No engine protection for intake manifold temperature. Possible smoke at engine start-up and no-load operation.
154	Intake Manifold Temperature Sensor #1 Circuit - shorted low (left bank).	No engine protection for intake manifold temperature. Possible smoke at engine start-up and no-load operation.	Warning	No engine protection for intake manifold temperature. Possible smoke at engine start-up and no-load operation.
155	Intake Manifold Temperature #1 High - Critical.	Voltage signal indicates intake manifold temperature has exceeded the shutdown threshold for high intake manifold temperature (left bank). Engine will shut down. High engine temperature relay driver is energized.	Shutdown	Engine will shut down. High engine temperature relay driver is energized.
159	Intake Manifold Temperature Sensor #2 circuit - Shorted high (right bank).	No engine protection for intake manifold temperature. Possible smoke at engine start-up and no-load operation.	Warning	No engine protection for intake manifold temperature. Possible smoke at engine start-up and no-load operation.
161	Intake Manifold Temperature Sensor #2 Circuit - Shorted low (right bank).	No engine protection for intake manifold temperature. Possible smoke at engine start-up and no-load operation.	Warning	No engine protection for intake manifold temperature. Possible smoke at engine start-up and no-load operation.
166	Rack Position Sensor #1 Circuit - Shorted high (left bank).	No action is taken by the ECM. Engine could possibly run rough.	Warning	No action is taken by the ECM. Engine could possibly run rough.
167	Rack Position Sensor #1 Circuit - Shorted low (left bank).	No action is taken by the ECM. Engine could possibly run rough.	Warning	No action is taken by the ECM. Engine could possibly run rough.
168	Rack Actuator Position #1 Circuit - Open circuit (left bank).	Engine will shut down.	Warning	Engine will shut down.
169	Rack Actuator Position #1 Circuit - Short circuit (left bank).	Engine will shut down.	Warning	Engine will shut down.
171	Fuel rack actuator position 1 circuit - data incorrect (left bank).	Performance could possibly be sluggish or slow to respond.	Warning	Performance could possibly be sluggish or slow to respond.
174	Rack Actuator Position #2 Circuit - Data incorrect (right bank).	Performance could possibly be sluggish or slow to respond.	Warning	Performance could possibly be sluggish or slow to respond.
179	Rack Position Sensor #2 Circuit - Shorted high (right bank).	No action is taken by the ECM. Engine could possibly run rough.	Warning	No action is taken by the ECM. Engine could possibly run rough.
181	Rack Position Sensor #2 Circuit - Shorted low (right bank).	No action is taken by the ECM. Engine could possibly run rough.	Warning	No action is taken by the ECM. Engine could possibly run rough.
182	Rack Actuator Position #2 Circuit - Short circuit (right bank).	Engine will shut down.	Warning	Engine will shut down.
183	Rack Actuator Position #2 Circuit - Open circuit (right bank).	Engine will shut down.	Warning	Engine will shut down.
197	Engine Coolant Level Low - Warning.	Voltage signal indicates low radiator coolant level. No action is taken by the ECM. Fault Code 146, 151, 228, and/or 233 could possibly also be logged.	Warning	No action is taken by the ECM. Fault Code 146, 151, 228, and/or 233 could possibly also be logged.
200	LOW OIL PRESSURE	Engine oil pressure dropped to unacceptable level.	Warning	If alternator powering critical loads and cannot be shut down, wait until next shutdown period and follow 201-SHUTDOWN procedure.
201	LOW OIL PRESSURE	Engine oil pressure dropped below shutdown trip point.	Shutdown	Check oil level, lines and filters. Replenish if low. Reset control and restart.
204	OIL PRES SENDER	Oil pressure sender out of working range.	Warning	Check that engine oil pressure sender is properly connected.
210	LOW COOLANT TEMP	Engine coolant temperature is 70°F (21°C) or lower.	Warning	Check coolant heater not operating or not circulating coolant. Check connections, coolant level, heater element.
211	HIGH COOLANT TEMP	Engine coolant temperature getting close to recommended maximum limit.	Warning	Reduce load if possible. Check air inlets and outlets. Follow HIGH COOLANT TEMP 212 shutdown procedure if engine can be stopped.
212	HIGH COOLANT TEMP	No engine protection for oil temperature.	Warning	No engine protection for oil temperature.
213	Engine Oil Temperature Sensor Circuit - Shorted low.	Resistance of coolant temperature sender out of range.	Warning	No engine protection for oil temperature.
214	LOW COOLANT LVL	Voltage signal indicates oil temperature has exceeded the shutdown threshold for high oil temperature. Engine will shut down.	Warning	Engine will shut down.
215	LOW COOLANT LVL	Engine coolant level fallen below trip point.	Shutdown	Check coolant level and replenish. Look for leaks. Reset control and restart.
219	Engine Oil Level #2 (remote) Low - Maintenance.	Low oil level is detected in the remote oil reservoir used in the Centinel™ system. Centinel™ system is disabled.	Warning	Centinel™ system is disabled.
220	MAG PICKUP	Mag pickup speed indication not sensed or does not match genset output frequency.	Shutdown	Restart and check RPM. Check wires and MPU adjustment.
221	FAIL TO CRANK	Possible fault with control or starting system.	Warning	No action is taken by the ECM. Possible loss of performance.
222	OVERCRANK	Possible fuel system problem.	Warning	No action is taken by the ECM. Possible loss of performance.
223	OVERSPEED	The Centinel™ actuator circuit is open or shorted. ECM turns off the Centinel™ actuator supply voltage, and the Centinel™ system is disabled.	Warning	Perform Rack Position Fault/Test Procedure.
228	Engine Coolant Pressure Low - Critical.	Voltage signal indicates coolant pressure has dropped below the shutdown threshold for low coolant pressure. Engine will shut down.	Shutdown	Engine will shut down.
2297	Fuel Supply Pump Driver Diagnostic has detected an error.	Priming pump is disabled. Possible loss of performance.	Warning	Priming pump is disabled. Possible loss of performance.
230	LOW DC VOLTAGE	Battery voltage below 24 VDC.	Warning	Check battery charger fuse. Recharge or replace battery. Clean battery cable connections. Check engine DC alternator.
231	HIGH DC VOLTAGE	No engine protection for coolant pressure.	Warning	No engine protection for coolant pressure.
232	WEAK BATTERY	No engine protection for coolant pressure.	Warning	No engine protection for coolant pressure.
233	Engine Coolant Pressure Low - Warning.	Voltage signal indicates coolant pressure has dropped below the warning threshold for low coolant pressure. Calibration-dependent engine shutdown occurs, or no action is taken by the ECM.	Warning	Calibration-dependent engine shutdown occurs, or no action is taken by the ECM.
234	Engine overspeed	Voltage signal indicates engine speed has exceeded the shutdown threshold for engine overspeed. Engine will shutdown. Overspeed relay driver is energized.	Shutdown	Fuel shutoff valves are de-energized (valves closed). Common Alarm output is energized. Overspeed relay driver is energized.
235	Engine Coolant Level Low - Critical.	Voltage signal indicates very low radiator coolant level. Engine will shut down.	Shutdown	Engine will shut down.
240	LOW FUEL-DAY	Day tank fuel supply running low.	Warning	Check fuel supply and replenish as required.
241	LOW FUEL	Fuel supply running low.	Warning	Check fuel supply and replenish as required.

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

Procedures

Analog Meter Calibration adjustment

Select >> from Main Menu, proceed to A−C VOLTS ADJ TO menu.
Start generator set and allow to reach normal operating speed.
Calibrate analog Voltmeter to digitally displayed value.
Calibrate analog % Amps meter to digitally displayed value.
Calibrate analog % Load meter to digitally displayed value.
Calibrate analog Frequency meter to digitally displayed value.
SAVE, then EXIT.

Cooling Fan Drive Belt Adjustment - Back Side Idler System adjustment

⚠ Do NOT tighten the inner jam nut excessively; the spring retainer will bend and the control rod will fail.

⚠ The fan belt idler is under tension. Do NOT allow your hands between the idler and belt or fan hub.

Tools: Socket and breaker bar

The fan belt must be installed and under fan idler arm spring tension.
Turn the adjusting screw until the end of the slot on the lower control rod end touches the spacer.
Note that one of the nuts has left-hand threads.
Hold the adjusting screw and tighten the two jam nuts.
For control rod with spring, turn the inner jam nut until spring retainer washers touch the cylinder.
Hold the inner jam nut and tighten the outer jam nut.

Crosshead Adjustment adjustment

⚠ The adjusting screw must not turn when the lock nut is tightened.

Tools: Torque wrench, Torque wrench adapter ST669

Adjust crossheads before adjusting valves, on the cylinder with both valves closed.
Loosen the crosshead adjusting screw locknuts on intake and exhaust.
Turn the adjusting screw out at least one turn.
Hold the crosshead down against its guide.
Turn the adjusting screw in until it touches the valve stem top without raising the crosshead.
Hold the screw and tighten the locknut to the specified torque.
Torque value with adapter ST669: 45 N-m [35 ft-lb].
Torque value without adapter: 60 N-m [45 ft-lb].

Digital Ammeter Display Calibration adjustment

Tools: calibrated ammeter

Select >> from Main Menu, proceed to AMPS L1 menu.
With generator set OFF, attach calibrated ammeter to L1.
Start generator set and allow to reach normal operating speed.
Load generator set to maximum rated kVA at rated voltage.
Calibrate AMPS L1 reading to agree with calibrated ammeter.
Repeat steps 17 through 20 for L2 and L3.
Select EXIT if no calibration; SAVE then EXIT if calibration made.

Digital Coolant Temperature Display Calibration adjustment

Tools: precision resistor (engine sensor calibration tool)

With generator set OFF, replace coolant temperature sender with precision resistor in calibration tool.
Select >> from Main Menu, proceed to COOLANT TEMP L menu.
Calibrate temperature reading to match calibration tool.
Repeat step 32 for COOLANT TEMP R if engine uses two sensors.
Select EXIT if no calibration; SAVE then EXIT if calibration made.

Digital Power Factor Display Calibration adjustment

Tools: power factor meter

Select >> from Main Menu, proceed to PF1 menu.
With generator set OFF, attach power factor meter to L1.
Start generator set and allow to reach normal operating speed.
Load generator set to maximum rated kVA at rated voltage.
Calibrate PF1 reading to agree with power factor meter.
Repeat steps 24 through 27 for L2 and L3.
Select EXIT if no calibration; SAVE then EXIT if calibration made.

Digital Voltage Display Calibration adjustment

Tools: calibrated frequency/voltmeter

Select >> from Main Menu, proceed to VOLTS L12 menu.
With generator set OFF, attach calibrated frequency/voltmeter to AC output L1 to L2.
Start generator set and allow to reach normal operating speed.
Calibrate VOLTS L12 reading to agree with calibrated voltmeter.
Shut generator set OFF.
Repeat steps 10 through 13 for L23 and L31.
Select EXIT if no calibration; SAVE then EXIT if calibration made.

Engine Torque Adjustment adjustment

Select >> from Main Menu, proceed to Torque Adjust %DC menu.
Start generator set and allow it to reach normal operating speed.
Load generator set to maximum rated kVA at rated voltage.
Adjust torque limit up or down to achieve proper generator set frequency under maximum load.

Magnetic Pickup Adjustment adjustment

⚠ Jam nut over-torque will damage the magnetic pickup.

Tools: Feeler gauge, Tap, Magnet

Ensure a ring gear tooth is centered under magnetic pickup hole.
Screw magnetic pickup in until it contacts the targeted gear tooth.
Back magnetic pickup out 1/2 to 3/4 turn counterclockwise.
If feeler gauge can be inserted, back out 0.71 to 1.07 mm from gear tooth.
Tighten jam nut while holding magnetic pickup.

Valve Adjustment (Overhead Set) adjustment

⚠ Use the correct firing order for the engine being serviced or parts will be damaged.

Tools: Feeler gauge, Torque wrench, Inch pound torque wrench 3376592, Torque wrench adapter ST669

Steam clean engine to prevent dirt entering when covers are removed.
Remove the rocker lever covers and all related components.
Rotate engine clockwise until the damper mark aligns with the pointer.
Identify the cylinder with both valves closed and rocker levers loose.
Loosen the valve adjusting screw locknut.
Insert the correct feeler gauge: intake 0.43 mm, exhaust 0.80 mm.
Tighten locknut to 60 N-m [45 ft-lb] without adapter; recheck clearance.
Install the rocker lever cover with a new gasket; torque 7 N-m [62 in-lb].

Voltage and Frequency Adjustment adjustment

Tools: calibrated frequency/voltmeter

Attach calibrated frequency/voltmeter to AC output L1 to L2 with generator set OFF.
Select ADJUST from Main Menu to display VOLTAGE adjust menu.
Start generator set and allow to reach normal operating speed.
Adjust VOLTAGE so calibrated voltmeter reads desired voltage.
Select Frequency adjust menu.
Verify frequency on calibrated meter is desired frequency. Adjust if not.
Select EXIT if no adjustment; SAVE then EXIT if adjustment made.

Fault Flash Out diagnostic

First active fault code is flashed out 3 times consecutively.
Process advances to next active fault code and flashes it 3 times.
After all active faults displayed, process starts over with first fault.
Cyclical display continues while Diagnostic Mode is active.

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

Voltage reconnection

Connection	Leads	Notes
Connector A, pin 12	Oil Pressure Sensor Signal
Connector A, pin 14	Coolant Temperature Signal
Connector A, pin 21	ESS + Signal	Engine Speed Sensor
Connector A, pin 22	ESS - Signal	Engine Speed Sensor
Connector A, pin 39/40	Fuel Shutoff Supply +24VDC (left bank pin 39, right bank pin 40)
Connector A, pins 31-34	DSR (31), RXD (32), TXD (33), DTR (34)	Datalink connector
Connector B, NC pins	4, 5, 22, 23, 40	No connection
Connector B, pin 1	Alarm Reset Signal	Customer supplied switch; grounds to reset alarms/warnings and inactive fault codes
Connector B, pin 10	Common Warning Relay Output (N/O)
Connector B, pin 11	Speed Adjust +5VDC Supply	Remote speed adjust potentiometer
Connector B, pin 12	Speed Adjust Signal	Potentiometer center wiper; 500 to 5000 ohms
Connector B, pin 13	Speed Adjust Return
Connector B, pin 14	Coolant Temperature Meter Driver	0-1mA meter output
Connector B, pin 15	Speed Bias Reference Supply (7.75VDC)
Connector B, pin 16	Speed Bias Input (Woodward)
Connector B, pin 17	Speed Bias Reference Supply (5.0VDC)
Connector B, pin 18	Speed Bias Input (Barber-Colman)
Connector B, pin 19	Shield
Connector B, pin 2	Alternate Frequency Signal	Customer supplied switch; ground to select alternate frequency
Connector B, pin 21	Tachometer Meter Driver	0-1mA meter output
Connector B, pin 24	Run Signal (switched B+)	Customer supplied Run/Stop input, 24VDC
Connector B, pin 3	Idle/Rated Signal	Ground to select idle speed mode
Connector B, pin 30	Ground
Connector B, pin 35	High Coolant Temperature Relay Driver	Rated 200mA max at 24VDC
Connector B, pin 36	Low Oil Pressure Relay Driver	Rated 200mA max at 24VDC
Connector B, pin 37	Engine Overspeed Relay Driver	Rated 200mA max at 24VDC
Connector B, pin 38	Pre-High Coolant Temperature Relay Driver	Rated 200mA max at 24VDC
Connector B, pin 39	Pre-Low Oil Pressure Relay Driver	Rated 200mA max at 24VDC
Connector B, pin 6	Oil Pressure Meter Driver	0-1mA meter output
Connector B, pin 7	Common Alarm Shutdown Relay Return

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

How many kW is the Cummins/Onan QST30?

The Cummins/Onan QST30 is rated 895 kW standby (1200.0 kVA).

What is the coolant capacity of the Cummins/Onan QST30?

The Cummins/Onan QST30 cooling system holds 114 liters (30.1 US gallons) for the radiator system including the engine, per the manufacturer specification sheet.

How much oil does the Cummins/Onan QST30 take?

The Cummins/Onan QST30 has an engine oil capacity of 154 liters (162.7 US quarts), per the manufacturer specification sheet.

What is the continuous rating of the Cummins/Onan QST30?

The Cummins/Onan QST30 is rated 806 kW prime (1000 kVA), against 895 kW standby.

How much does the Cummins/Onan QST30 weigh?

The Cummins/Onan QST30 has a dry weight of 3565 kg (7859 lb).

What voltages is the Cummins/Onan QST30 available in?

The Cummins/Onan QST30 is offered in 50 V, 60 V.

What alternator does the Cummins/Onan QST30 use?

The Cummins/Onan QST30 uses a 35 amps alternator.

Which oil filter part number does the Cummins/Onan QST30 take?

The Cummins/Onan QST30 uses oil filter part number 3375049.

Troubleshooting

Fault codes

Code	Meaning	Remedy
RAIN	Rain	Repair as soon as convenient
SOE	System Over-ride Event
0	Check electronic engine controls (fault code lamp)

Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.

Parts

Part #	Description	Qty	System
19200074	Buzzer		Engine harness adaptor cable	Amazon eBay
19a00292	Engine Speed Sensor		Engine speed sensor	Amazon eBay
19a00295	Fuel Shut-Off Valve		Fuel shut off valve	Amazon eBay
19a00296	Rack Position Actuator (integral to the RP39 fuel pump)		Rack position actuator	Amazon eBay
19a00297	Meter Drivers		Meter drivers	Amazon eBay
19a00Z25	Fuel Pump Rack Actuator Valve		Fuel pump rack actuator valve	Amazon eBay
3375049	Oil Filter Wrench	1	Oil filter	Amazon eBay
3377193	Battery Tester	1	Battery tester	Amazon eBay
4900294	Oil Pressure Sensor		Oil pressure sensor	Amazon eBay $74.95
49400355	Common Warning Circuit		Common warning circuit	Amazon eBay
49400356	Sleeve Position Activator (integral to the RP39 fuel pump)		Sleeve position activator	Amazon eBay
49400361	Common Alarm Circuit		Common alarm circuit	Amazon eBay
5572670	Thermostat Seal Installation Tool		Thermostat	Amazon
78000067	Coolant Temperature Sensor		Coolant temperature sensor	Amazon eBay
ST1225	Thermostat Seal Driver	1	Thermostat	Amazon eBay
ST669	water pump type grease listed below, or its equivalent	1	Belt	Amazon eBay $204.59
17800008	Component weighs 23 kg [50 lb] or more. To avoid personal injury, use a hoist or get assistance to lift the component.		Service part / kit	Amazon eBay
3375432	Crack Detection Kit	1	Service part / kit	Amazon eBay
3375434	Crack Detection Developer	1	Service part / kit	Amazon eBay
3666134	QST30 & M Manual		Service part / kit	Amazon eBay
3666184	QST30 G-Drive Fuel System T & R Manual		Service part / kit	Amazon eBay
3666185	QST30 G-Drive Wiring/Fault Code Diagram		Service part / kit	Amazon eBay
3666196	INSITE™ For QST30 G-Drive User's Manual		Service part / kit	Amazon eBay
3666242	QST30 G-Drive Pocket Fault Code Cards		Service part / kit	Amazon eBay
3672102	QST30-G1/G2/G3 Parts Manual		Service part / kit	Amazon eBay
3884904	QST30 G-Drive Engine Installation Requirements		Service part / kit	Amazon eBay
C2800	Fleetguard® refractometer	1	Service part / kit	Amazon eBay NAPA $393.59

Service, wear & replacement parts referenced for this model and its engine — confirm the exact part for your serial number. See the full parts catalog to search and cross-reference.

Fuel consumption

Rating	Load	L/h	gal/h
Prime	100%	228.0	60.2
Standby	100%	204.0	53.9

Available documents

Engine spec — 0032276 (Cummins/Onan)Spec sheet — 0070621 (Cummins/Onan)Spec sheet — Cummins-750DFHA-QST30-G2-spec-sheet (Cummins/Onan)Spec sheet — Cummins-800DFHB-with-QST30-G2-Engine-Spec-Sheet-S-1135 (Cummins/Onan)Spec sheet — Cummins-DQFAD-1000-kW-QST30-G5-NR2-open-skid-engine-driven-radiator-submittal.pd (Cummins/Onan)Spec sheet — Cummins 1000 kW QST30 G5 engine rental power spec sheet (Cummins/Onan)Spec sheet — QST30-G3 (Cummins/Onan)Spec sheet — QST30-G3 0 (Cummins/Onan)Reference — 0032425 (Cummins/Onan)Reference — 0059591 (Cummins/Onan)Reference — QST30 nuevo (Cummins/Onan)Reference — Schedule Technical2012 (Cummins/Onan)Owner's manual — Cummins Diesel QST30 Manual 1997 (Cummins/Onan)Parts manual — {5bc4040d-d72a-4ebb-81b9-034afcefa4a9} Cummins Mechanical Electrical Service Tools June 2019Service manual — B20BiodieselFAQJan2009 (Cummins/Onan)Service manual — CUMMINS DIESELS QST30 Generator Drive Fuel Control Governor 1998 (2) (Cummins/Onan)Service manual — CUMMINS QST30-G Control Manual 2003 (2) (Cummins/Onan)Service manual — Cummins-DFHA-DFHB-DFHC-DFHD-spec-A-thru-J-service-manual-QST30-engine-with-PowerCommand-3.1-control (Cummins/Onan)Service manual — ServiceInstructions5 (Cummins/Onan)

This page was generated from the 19 manufacturer documents above by automated extraction; every figure shown is copied from one of them. How the data is compiled.

Cummins/Onan QST30 Generator Set

Service parts for the QST30

Oil system

Belts

Specifications

Maintenance & consumables

Service intervals

Service specifications

Recommended fluids

Fault codes

Procedures

Voltage reconnection

Common questions

Troubleshooting

Fault codes

Repair guides

Parts

Fuel consumption

Available documents