Cummins/Onan — Cooling System Clean
Maintenance
From a Cummins/Onan owner's manual covering: M11, M1i Series Engines, ps200da. Check it applies to your exact model before use.
Applies to: Cummins/Onan M11 engine
Before you start
- Do not use caustic cleaners in the cooling system. Aluminum components will be damaged.
- Wait until the temperature is below 50 C [120 F] before removing the coolant system pressure cap.
- Fleetguard RESTORE contains no antifreeze. Do not allow the cooling system to freeze during the cleaning operation.
Procedure
- Drain the cooling system. Do not allow the cooling system to dry out. Do not remove the coolant filter.
- Immediately add 3.8 liters [1 U.S. gal.] of Fleetguard RESTORE or RESTORE PLUS for each 38 to 57 liters [10 to 15 U.S. gal.] of capacity, and fill with plain water.
- Turn the heater temperature switch to high.
- 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 the cooling system with clean water.
- Operate the engine at high idle for five minutes with coolant temperature above 85 C [185 F].
- Shut off the engine and drain the cooling system.
- If water drained is still dirty, flush again until clean.
- Fill with fully formulated coolant or a 50/50 mixture of antifreeze and good quality water.
- Install the pressure cap, operate the engine until it reaches 80 C [180 F], and check for leaks.
Specs & values
- Operate at least 85 C [185 F] for 1 to 1-1/2 hours
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.