Cummins/Onan 12.0 RDJC — Draining Cooling System
Maintenance
For the Cummins/Onan 12.0 RDJC, from the Cummins/Onan operator's manual.
Applies to: Cummins/Onan RDJC
Before you start
- Drain only components not protected from freezing.
Procedure
- Open vent valve or vent plugs.
- Loosen the water pump cover and hose connections so water runs out.
- Drain the engine block by removing the 1/4-inch drain plug on the left front side of the engine.
- Drain the water manifold by removing the drain plug at the bottom.
- Disconnect hose clamps and hoses to aid draining.
- Flush out cooling system until water runs clearly.
- Reconnect hoses, reinstall drain plugs, and close vent valve or plugs.
Full service-parts list: Cummins/Onan RDJC →
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.