Mercedes-Benz V12 Biturbo M 279 AMG Introduction Into Service Manual page 49

Charge air cooling
If the charge air temperature exceeds 45 °C, the
charge air cooler circulation pump is actuated by
the ME-SFI control unit via the engine coolant circu-
lation pump relay.
i Note
For the charge air cooling system to operate
correctly, it is absolutely essential that the low-
temperature circuit is filled without bubbles!
For this purpose there is the special tool "vacuum-
type cooling system filler" and work instructions in
WIS describing the bleeding procedure in detail.
48 b Introduction of the New V12 Biturbo Engine, M 279 AMG
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When the charge air temperature drops below
35 °C, the coolant circulation pump is switched off
again.
The charge air temperature is registered in the
intake manifold by the charge air temperature
sensor and is sent to the ME-SFI control unit with a
voltage signal.
i Note
The cap of the low-temperature circuit may only be
opened when the engine is cold (ambient
temperature).
If the cap is opened while the engine is warm,
coolant escapes and air enters the low-tempera-
ture circuit. This results in a considerable power
loss, and the low-temperature circuit must then be
bled!