Cummins/Onan 10W30 — Draining and Flushing the Cooling System
Maintenance · Cooling system / radiator
For the Cummins/Onan 10W30, from the Cummins/Onan operator's manual.
Applies to: Cummins/Onan GGHE, Cummins/Onan GGHF, Cummins/Onan WSG-1068 engine
Before you start
- Some coolant is toxic. Follow local environmental regulations for disposal.
- The heater element will burn out if engine coolant is removed with heater connected to power source.
Procedure
- Disconnect engine coolant heater from power source (if equipped).
- Allow the engine to cool and then remove radiator pressure cap.
- Open the radiator drain cock and remove the water drain plugs (one on each side of engine).
- When coolant is drained, place the end of a water hose into the radiator filler and turn on water supply.
- Regulate flow until inflow equals outflow; continue flushing until outflow is clear of rust sediment.
- If equipped with engine coolant heater, drain coolant by removing hose and clamp from bottom of heater.
- Replace the water drain plugs and close the radiator drain cock; refill with recommended coolant.
Full service-parts list: Cummins/Onan GGHE →, Cummins/Onan GGHF →
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.