The valvetrain on the N52 introduced in 2006, used 5 mm valve stems on both
the intake and exhaust. To
increase durability, the exhaust valve stems were increased to 6 mm from 6/06
production.
All of the new NG6 engine have adopted the 6 mm valve stem for the exhaust, the
intake stem remains at
BMW maintenance system
The maintenance system provides service notifications
and thereby provides support in maintaining
road safety and the operational reliability
of the vehicle.
In some cases, scopes and intervals of the maintenance
system may vary according to the country
version. Replacement w