Cummins/Onan — Priming the oil system
Maintenance · lubrication system
From a Cummins/Onan operator's manual covering: 500 DFX-57R, 600 DFX-4R, 600 DFX-4XR, DFX 4R, DFX 4XR, DFX 57R, DFX 5DR, DFX 6DR, DFX 7XR, DFX 9XR. Check it applies to your exact model before use.
Applies to: Cummins/Onan 500 DFX-57R, Cummins/Onan 600 DFX-4R, Cummins/Onan 600 DFX-4XR, Cummins/Onan KT2300-G engine
Procedure
- Remove oil inlet line from turbo-charger housing, fill bearing housing with clean oil, replace line, repeat for second turbo
- Fill crankcase to L (low) mark on dipstick
- Remove plug from head of oil filter housing and connect priming pump from clean lubricating oil source
- Prime until 30 psi (207 kPa) pressure is obtained
- Disconnect wire from fuel solenoid valve, close throttle, crank engine maintaining 15 psi (103 kPa) external prime for 15 seconds
- Remove external priming equipment, replace plug in filter housing, torque 15-20 lb-ft (20-27 N.m)
- Reconnect wire to fuel shut-off valve
- Complete oil fill to H (high) mark on dipstick
Tools required
- hand or motor-driven priming pump Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- 30 psi (207 kPa) prime pressure
- 15 psi (103 kPa) external prime pressure
- torque 15 to 20 lb-ft (20 to 27 N.m)
Full service-parts list: Cummins/Onan 500 DFX-57R →, Cummins/Onan 600 DFX-4R →, Cummins/Onan 600 DFX-4XR →
Source: Cummins/Onan operator's manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.