E 320 4MATIC Sedan (210.082) V6-3.2L (112.941) (1999)
Figure 2 Volume Control Valve (t30) Closed
ENGINE ON, STEERING WHEEL TURNED
The pressure behind the volume control valve also increases due to the increasing pressure level behind the restrictor (a). The volume control
valve (30t) closes (Figure 2) and remains in its initial position.
INCREASED ENGINE SPEED
If the oil quantity increases as engine speed increases, a greater pressure difference occurs again due to the calibrated bore (9a). The volume
control valve (30t) is pressed against the spring (30s) and the excess oil quantity delivered can flow back into the reservoir (Figure 1).
PRESSURE LIMITATION
A pressure limiting valve (49d) is installed in the volume control valve (30t) to protect the steering system against overload. It opens between a
pressure of 65 and 125 bar depending on the tune of newer steering pump.
This occurs at full steer angle for example, which is audible as a shrill whirring whistling sound.