The Cummins/Onan RDJF is a 2.3 L 4-cylinder naturally aspirated engine rated at 1800 rpm. It powers generator sets from Cummins/Onan, including the 17.5RDJF-3CR. It holds 11.36 L (3.0 gal) of oil and 11.36 L (3.0 gal) of coolant.
Also known as: Onan RDJF
| Oil capacity | 11.36 L |
|---|---|
| Coolant capacity | 11.36 L |
| Displacement | 2.3 L |
| Cylinders | 4 |
| Aspiration | Naturally Aspirated |
| Rated speed | 1800 rpm |
How to read your Cummins/Onan engine serial & model number →
| Symptom | Cause | Remedy |
|---|---|---|
| Engine does not crank. | Battery dead, loose connections, incorrect wiring, or faulty starter motor. | Check 12 VDC to ground at battery BT1 and at starter motor Bl. Check B+ present at TB11, K13, S1, and M11. Check battery cables for polarity and tightness at battery and starter motor. If battery is dead, check if centrifugal switch S1 is open to ground. Replace S4 or charge battery. Jumper battery cable connection to ground at starter. Check starter motor. With S11 at START, jumper K11 contacts to starter solenoid. Start relay K11 is defective; replace it. |
| Engine cranks but does not start. | Faulty switch or lead connections. | Check 12 VDC present between start terminal on S11 and ground (TB11-1) with S11 at START. Check 12 VDC present between M11-B+ and ground TB11-1 with S11 at START. Replace faulty switch S11 if necessary. Check lead from TB12-4 to fuel pump; check fuel pump and replace if necessary. |
| Engine starts but stops when start switch is released. | Faulty switch or lead connections. | Connect voltmeter from 12 VDC to ground at battery BT1 and at starter motor Bl. Check B+ present at TB11, K13, S1, and M11. Check battery cables for polarity and tightness at battery and starter motor. If battery is dead, check if centrifugal switch S1 is open to ground. Replace S4 or charge battery. Jumper battery cable connection to ground at starter. Check starter motor. With S11 at START, jumper K11 contacts to starter solenoid. Start relay K11 is defective; replace it. |
| No build up of AC output voltage. | Is Field Breaker CB21 on control panel ON? If not, step 2. Connect jumper wire across terminals of Field Breaker, CB21. Does AC output voltage build up? If yes, replace Field Breaker. If no, push to reset Field Breaker. Does AC output voltage build up? If yes but is high, low, unstable, or causes tripping of Field Breaker, refer to Tables B, C, or D. If no, step 4. Disconnect alternator stator leads 1 & 2 from TB21-1 and TB21-2 on VR22. Is reference voltage across 1 & 2 20 VAC or more? If not, refer to step 14. | |
| AC output voltage builds up, but is unstable. | Are there any loose or broken wires or connections on voltage regulator assembly VR22? If yes, step 3. Is W9 (exciter field) wiring harness from VR22 to End bell OK? If no, replace PC Board VR21. Do not replace the printed circuit board until the trouble not on the PC board has been located and corrected to avoid damage to new PC board. | |
| AC output voltage builds up, but is high or low. | Is set running at correct RPM? (See appropriate engine manual to set RPM) If no, step 3. Does adjustment of Voltage Adjusting knob for R22 on VR22 result in correct output voltage? If no, step 4. Does adjustment of potentiometer R26 on VR21 result in correct output voltage? If no, refer to step 5. Is correct voltage reference V4 to V1, V2, or V3 on VR21 being used? Refer to Figure 6. If no, replace voltage regulator PC board VR21. Do not replace the printed circuit board until the trouble not on the PC board has been located and corrected to avoid damage to new PC board. | |
| AC output voltage builds up, but Field Breaker trips. | Does AC output voltage build up to 140% or more of rated voltage before Field Breaker trips? If yes, are there any loose or broken wires or connections on VR22? If no, is diode CR15 on VR21 OK? If no, are T21 windings and connections OK? If no, are generator stator leads properly connected? Refer to Figure 6. Replace VR21 if necessary. Are diodes CR1, CR2, CR3, CR4, CR5, CR6 in rotating rectifier assemblies OK? Check all diodes - more than one may be defective. Is brushless exciter stator winding OK? Is generator rotor field winding OK? If no, is brushless exciter rotor windings OK? |
Fault codes and symptom→remedy steps extracted from this engine’s service/owner documentation; verify against the official manual before servicing.
| Item | Spec | Capacity | Part # | Interval | |
|---|---|---|---|---|---|
| Air filter | Dry | — | |||
| Oil filter | Full Flow Type | — | |||
| Oil | Type: Light | 11.36 quarts | — |
Pooled from every document that names this exact engine — confirm the interval and part number against your unit's serial number.
The Cummins/Onan RDJF engine has an oil capacity of 11.36 liters.
The Cummins/Onan RDJF has a displacement of 2.3 liters with 4 cylinders.
The Cummins/Onan RDJF powers 1 generator set(s), including Cummins/Onan 17.5RDJF-3CR.