Loosen the oil pan mounting bolts. Remove the cover mounting bolts (1, Fig. 6.63) rear crankshaft oil seal. Loosen the bolt (2) and remove the crankshaft position sensor (3) in the direction indicated by the arrow.
Remove the rear oil seal cover and carefully detach the oil pan sealing gasket from the rear oil seal cover without damaging it. If necessary, remove the oil pan and replace the sealing gasket.
Attention! The seal must be stored on the support sleeve; a seal stored without a support sleeve for more than six months cannot be used.
Do not bend the working edge of the seal or touch it with your hands. The rear seal cover is supplied complete with the seal.
When installing the cover with the oil seal on the crankshaft, a support sleeve can be used as a mounting device (1, Fig. 6.64).
Lubricate the crankshaft mounting surface with engine oil. Install the crankshaft rear oil seal cover using the support sleeve (1) evenly, without distortions. Insert and tighten all oil seal cover mounting bolts. Check the correct position of the centering sleeves. Assemble the engine and check it for leaks.
[Information obtained from this online resource BMWman.ru]