- ATF oil of the specified specification.
The power steering fluid level should be checked every 10,000 km.
The oil level can be checked both with cold and with warm oil. The operating temperature of the oil is about +80°C, the temperature of cold oil corresponds to the ambient temperature.
With the engine off, unscrew the expansion tank cap. Wipe the oil dipstick on the cap with a clean, lint-free cloth.

With the cap on, the oil level should be between the marks on the dipstick. ATF is added (Automatic-Trnsmission Fluid) with the designation Dexron or Dexron II. It is necessary to add new oil, as even a small contamination can cause a malfunction of the hydraulic system.
The total filling capacity is about 1.2 liters.
Start the engine and add oil until the level is between the marks on the dipstick.
With the engine running, turn the steering wheel from lock to lock several times to remove air from the system.
Stop the engine. The oil level should then rise 5 mm above the upper mark. Check the sealing ring for cracks and damage.
Close the expansion tank.
[The original article is located on bmwman.ru]
