Cummins/Onan — Out-of-service protection (storage, up to six months)
Maintenance · engine
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
Before you start
- For storage beyond six months refer to Cummins Service manual
Procedure
- Start and operate engine until thoroughly warm; disconnect fuel lines to filter and injector drain line
- Start engine on diesel fuel, then switch to preservative oil and run 5-10 minutes, stop engine and reconnect fuel lines
- Drain oil sump, fuel filters and fuel tank, reinstall drain plugs
- Disconnect electrical wiring, turn fuel pump shutoff valve fully counterclockwise, spray lubricating oil into intake manifold while cranking slowly
- Cover all openings with tape
- Drain coolant unless permanent antifreeze with rust inhibitor is used
- Store engine in dry, uniform temperature area
- Bar engine crankshaft two or three revolutions every three to four weeks
Tools required
- tape Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
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.