Operation and maintenance manual

Cooling System QSB4.5 and QSB6.7
Page 7-6 Section 7 - Maintenance Procedures at 2000 Hours or 2 Years
Fill
CAUTION
The system must be filled properly to prevent air
locks. During filling, air must be vented from the
engine coolant passages. Wait 2 to 3 minutes to allow
air to be vented; then add mixture to bring the level to
the top.
To be sure air is vented during the fill process:
•
The thermostat has check balls that allow air to vent
through the thermostat when the thermostat is
closed.
•
A deaeration port is located next to the water outlet
connection which connects to the top tank/coolant
recovery tank of the cooling system.
The system has a design fill rate of 19 liters [5 gal.] per
minute.
CAUTION
Never use water alone for coolant. Damage from
corrosion can be the result of using water alone for
coolant.
Use a mixture of 50-percent water and 50-percent
ethylene glycol or propylene glycol antifreeze to fill the
cooling system. Refer to the Cummins Coolant
Requirements and Maintenance, Bulletin 3666132, for
engine coolant specifications.
For cooling system capacity, refer to Procedure 018-018
(Cooling System) in Section V.
WARNING
Do not remove the pressure cap from a hot engine.
Wait until the coolant temperature is below 50°C
[122°F] before removing the pressure cap. Heated
coolant spray or steam can cause personal injury.
Install the pressure cap. Operate the engine until it
reaches a temperature of 80°C [180°F] and check for
coolant leaks.
Check the coolant level again to make certain the system
is full of coolant or that the coolant level has risen to the
hot level in the recovery/expansion tank in the system, if
so equipped.