Cummins/Onan — Closed Water System Maintenance
Maintenance · Heat exchanger / closed water system
From a Cummins/Onan service manual — check it applies to your exact model before use.
Applies to: Cummins/Onan MCCK
Procedure
- Maintain closed water system same as automotive radiator cooling system.
- Clean and flush once a year.
- Use anti-freeze if there is danger of freezing.
- Use a rust inhibitor in the closed water system.
Full service-parts list: Cummins/Onan MCCK →
Source: Cummins/Onan service 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.