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Charge air cooling system, function - GF09.41-P-3104MOS

ENGINE 275.953 in MODEL 216.376, 221.176 as of Model Year 09 /AEJ 08 

ENGINE 275.982 in MODEL 216.379, 221.179 as of Model Year 09 /AEJ 08 

Charge air cooling function requirements - general 

Charge air cooling - general 

The charge air cooling holds the charge air temperature below 70°C.

The cooled air downstream of the charge air coolers has higher density. This increases the cylinder charge, and therefore engine performance. It also reduces the tendency to knock, and the lower exhaust temperatures reduce the formation of nitrogen oxides (NO X ).

One water/charge air cooler is installed for each cylinder bank. Both water/charge air coolers are connected to the low-temperature cooling circuit with low-temperature cooler and circulation pump charge air cooler (M44).

Charge air cooling function sequence 

If the charge air temperature is above 47°C, the ME-SFI control unit (N3/10) actuates the charge air cooler circulation pump through the circulation pump relay (N10/2kQ).

If the charge air temperature falls below 35°C, the charge air cooler circulation pump is switched off again.

The charge air temperature in the intake manifold is detected by the charge air temperature sensor (B17/8) and sent to the ME-SFI control unit (N3/10) in the form of a voltage signal.

IMPORTANT The charge air cooling function crucial depends on bubble-free filling of the low-temperature cooling circuit. A special tool (vacuum pump) is required for filling this circuit.

IMPORTANT Only open the cap on the low-temperature coolant circuit when the charge air temperature is increased (lack of power) and the engine is cold. The coolant must reach up to the cap.

Shown on charge air cooling model 240 

Fig 1: Charge Air Cooling System Function Diagram
G07630310Courtesy of MERCEDES-BENZ USA
  ME-SFI [ME] control unit, component description N3/10 GF07.61-P-6000MOS