Cummins/Onan — Draining and Flushing the Radiator
Maintenance · Cooling system
From a Cummins/Onan operator's manual — check it applies to your exact model before use.
Applies to: Cummins/Onan GGHG, Cummins/Onan GGHH, Cummins/Onan V-10 WSG-1068 engine
Before you start
- Some coolant is toxic. Keep away from children and animals. Follow local environmental regulations for disposal.
- The heater element will burn out if engine coolant is removed with heater connected to power source.
- The heater element will burn out if power is connected before it is filled with coolant or if straight antifreeze solution is used for coolant.
Procedure
- Disconnect engine coolant heater from power source (if equipped).
- Allow the engine to cool and remove the radiator pressure cap.
- Open the radiator drain cock and remove the water drain plugs (one on each side of engine).
- Place the end of a water hose in the radiator filler and turn on the water supply.
- Regulate flow until inflow equals outflow from drain openings; continue flushing until outflow is clear of rust sediment.
- Replace the water drain plugs and close the radiator drain cock.
- Refill the cooling system with the recommended coolant.
- After engine has run, connect heater plug to receptacle.
Full service-parts list: Cummins/Onan GGHG →, Cummins/Onan GGHH →
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.