Cummins/Onan QST30 — Cooling System Clean (Flush)
Maintenance
For the Cummins/Onan QST30, from the Cummins/Onan owner's manual.
Applies to: Cummins/Onan G-Drive, Cummins/Onan QST30, Cummins/Onan QST30 engine
Before you start
- Do not use caustic cleaners; aluminum components will be damaged.
- Wait until coolant temperature is below 50 C [120 F] before removing the pressure cap.
Procedure
- Drain the cooling system; do not allow it to dry out.
- Add 3.8 liters [1 U.S. gal] Fleetguard RESTORE per 38 to 57 liters [10 to 15 U.S. gal] capacity.
- Fill the system with plain water.
- Operate the engine at least 85 C [185 F] for 1 to 1-1/2 hours.
- Shut off the engine and drain the cooling system.
- Fill with clean water and run at high idle five minutes above 85 C.
- Drain again; repeat flushing until drained water is clean.
- Refill with fully formulated coolant or 50/50 antifreeze mixture.
Specs & values
- RESTORE 3.8 liters [1 U.S. gal] per 38 to 57 liters [10 to 15 U.S. gal] capacity
Full service-parts list: Cummins/Onan QST30 →
Source: Cummins/Onan owner'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.