Operation and maintenance manual

QSB4.5 and QSB6.7 Cooling System
Section 5 - Maintenance Procedures at 500 Hours or 6 Months Page 5-9
Figure 1: Sequence of Events for Coolant Fill and Deaeration.
NOTE: If all coolant drained from the system was collected, the same volume or more must go back into the system.
If any drained coolant remains after filling, this is an indication of an air pocket which must be purged before returning
the vehicle to service.
Unless indicated otherwise by OEM instructions, it is critical that all shutoff valves be returned to their open positions
once the system has been refilled and the deaeration process is about to begin. This will help to make sure as much
air as possible will be purged from the heating circuit. See the OEM service manual for valve locations.
Wait 2 to 3 minutes, without starting the engine, to allow the system to naturally purge entrained air and for the coolant
level to stabilize.
Add 50/50 mixture to bring the coolant level back to the FULL cold level.
Turn all cab heater switches to HIGH in order to allow maximum coolant flow through the heater core(s). The blower
MUST be turned ON.
With the cooling system fill cap removed:
• Operate the engine at LOW IDLE for 2 minutes.
• Shut the engine OFF and add coolant to bring the level back to the FULL cold level, using 50/50 mixture.
With the cooling system fill cap removed:
NOTE: After starting a cold engine, increase the engine speed (rpm) slowly to provide adequate lubrication to the
bearings and to allow the oil pressure to stabilize.
• Start the engine.
• Operate the engine at HIGH IDLE until the thermostats open.
Allow the engine to idle 2 minutes before shutting it down. This allows adequate cool down of pistons, cylinders,
bearings, and turbocharger components.
• Shut the engine OFF.
• Top off coolant to the FULL hot level.
• It is the responsibility of the customer to check the cold coolant level and top up if necessary.
NOTE: Certain applications may require an additional 10 minutes of operation time at HIGH IDLE for complete
deaeration. For best results, reference the OEM coolant fill procedure for specific instructions.
Install the pressure cap. Operate the engine until it reaches a temperature of 80°C [176°F] and check for coolant
leaks.
Reference Figure 1 for a graphic explanation of the fill process.