On my rig, I need to run the dash heater on high and allow air to expel via the vent mounted just behind the surge tank to remove air pockets.
Trust me, burping the system was necessary as I spent nearly $400 in unsuccessful diagnostics at Allison and Cummins before accidentally learning that after replacing the coolant the Tech had not burped the engine......
The instructions were in the Cummins engine manual and on the Surge Tank.
I filled my system via the surge tank.
1995 38' CC Magna #5280
C8.3L 300hp Cummins, 31,000lbs
Gillig Bus Chassis