Diagnosis And Testing: DEAERATION
NOTE:
Deaeration occurs at higher engine speeds, not at idle. Normal driving will deaerate the cooling system.
As air is removed from the cooling system, it gathers in the pressurized coolant bottle. This pressure is released into the atmosphere through the pressure valve located in the radiator pressure cap when pressure reaches 1.4 bar (20.3 psi).
To effectively deaerate the system, multiple cycles of the thermostat opening and closing may be required.