Operation and maintenance manual

QSB4.5 and QSB6.7 Cooling System
Section 5 - Maintenance Procedures at 500 Hours or 6 Months Page 5-7
Shut the engine OFF, allow the cooling system to cool to
50°C [122°F].
Drain the cooling system.
NOTE: If the water being drained is still dirty, the system
must be flushed again until the water is clean.
Fill
CAUTION
The system must be filled properly to prevent air
locks or serious engine damage can result. 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.
Make 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.
• An air vent port connection, which connects to the top
tank/coolant recovery tank of the cooling system, is
located next to the water outlet.
The system has a designed 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. Verify the coolant recommendations and
specifications. Refer to Procedure 018-004 in Section V.