Cummins/Onan — Cleaning Closed Water System

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

1. Drain and fill with radiator cleaner.
2. After chemical cleaning, always flush cooling system to wash out loosened deposits.
3. Flush engine water jacket.
4. Remove water outlet hose from engine water jacket to heat exchanger.
5. Flush both open and closed water system sides of heat exchanger.
6. Remove rubber impeller pump cover to flush open system.
7. Flush water-cooled exhaust manifold.
8. Check system thoroughly for leaks.

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.

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