Cummins/Onan — Flushing and Cleaning Cooling System
Maintenance
From a Cummins/Onan operator's manual covering: 5.0 MDKUB, 6.0 MDKUB, 7.5 MDKWB, 9.0 MDKWB. Check it applies to your exact model before use.
Applies to: Cummins/Onan 5.0 MDKUB, Cummins/Onan 6.0 MDKUB, Cummins/Onan 7.5 MDKWB, Cummins/Onan 9.0 MDKWB, Cummins/Onan MDKUB, Cummins/Onan MDKWB, Kubota Z482B engine, Kubota D722B engine
Before you start
- Never pour hot water into a cold engine or cold water into a hot engine.
- Do not operate the unit without water.
Procedure
- Open heat exchanger drain and cylinder block drain.
- Remove pressure cap to aid draining.
- Drain system completely.
- Chemical cleaning: use good cleaning compound per instructions if rust/scale.
- Flushing: fill with clean water, run genset 10 minutes, drain completely.
- Refill with coolant mixture.
Full service-parts list: Cummins/Onan 5.0 MDKUB →, Cummins/Onan 6.0 MDKUB →, Cummins/Onan 7.5 MDKWB →, Cummins/Onan 9.0 MDKWB →, Cummins/Onan MDKUB →, Cummins/Onan MDKWB →, Kubota Z482B engine →
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.