Do not hold the steering wheel fully turned in one direction or the other for more than five seconds. This may damage the steering pump.
2. The power steering system reservoir is located in the engine compartment and has a screw-on cap with a measuring probe built into it.
Model 320d: Oil reservoir cap (arrow on the illustration) is located in front of the oil level indicator, when looking in the direction of travel.
Petrol models: The reservoir is located in the area between the engine and the radiator.
3. Park the vehicle on a level surface and apply the parking brake.
4. When the engine is cold, the fluid level should be near the MIN mark. The permissible deviation of the fluid level on the dipstick from the MIN mark is ±2 mm.
5. Start the engine and warm it up to normal temperature. With the engine idling, turn the steering wheel from lock to lock several times to bleed the air from the steering system. Turn off the engine, remove the reservoir cap by turning it counterclockwise, wipe the dipstick dry and close the cap. Open the cap again and check the fluid level. It should be between the two marks.
6. Add liquid in small doses until it reaches the desired level.
Do not allow the liquid to overflow. If this does happen, remove the excess with a clean syringe. Close the lid.
7. If frequent fluid additions are required, check the power steering hoses and fittings for signs of wear and leaks (refer to Section Checking the condition and replacing the engine compartment hoses).
8. Check the condition and tension of the drive belt (refer to Section Checking the condition of ribbed drive belts).