Operation and maintenance manual

Cooling System QSB4.5 and QSB6.7
Page 5-4 Section 5 - Maintenance Procedures at 500 Hours or 6 Months
Flush
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.
To be sure air is vented during the fill process:
• Some thermostat have 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.
This provides adequate venting for a fill rate of 19 liters [5
gal] per minute.
NOTE: An alternate to using sodium carbonate, as
outlined in this procedure, is to use Restore™.
Restore™ is a heavy-duty cooling system cleaner that
removes corrosion products, silica gel, and other deposits.
The performance of Restore™ is dependent on time,
temperature, and concentration levels. An extremely
scaled or flow-restricted system, for example, can require
higher concentrations of cleaners, higher temperatures,
longer cleaning time, or the use of Restore Plus™. Up to
twice the recommended concentration levels of Restore™
can be used safely. Restore Plus™ must be used only at
its recommended concentration level. Extremely scaled or
fouled systems can require more than one cleaning.
NOTE: Do not install the radiator cap. The engine is to be
operated without the cap for this process.