Attention! The car must not be loaded.
1. Turn off the ignition.
2. Remove the cap (1) on the expansion tank (2) and take out the level indicator.
3. Wipe the pointer with a cloth and reinsert it until it stops.
4. Remove the dipstick and use it to determine the oil level.
5. When the oil is cold, its level should be between the "MIN" and "MAX" marks (4/3) of the indicator. The oil is considered cold if its temperature is approximately +20°C.
6. If necessary, add oil to the system. Only new oil should be added, as even minor contamination can lead to malfunctions in the hydraulic system.
7. When filling the system with oil, use a clean funnel and a fine-mesh sieve.
(Material borrowed from an online resource: MERCEDESMAN.ru)