M62 B46 only:
WARNING: This page is about a different car, the 2003 BMW X5, 2002 BMW X5, 2001 BMW X5, and 2000 BMW X5. However, it is still accessible from the selected car via links, so may be relevant.
Lightly coat pistons and piston rings with oil.
Align contact points of piston rings (offset at approx. 120°, but not over piston pin lug).
Compress piston rings with special tool 11 9 500.
Keep piston rings compressed with special tool 11 9 500.
Install piston so that arrow points to camshaft drive.
IMPORTANT:
Danger of piston ring failure.
Press in piston only with finger force (do not knock in!).