The N54 and N52KP meet ULEV II requirements for 2007. There are not many
changes to the emission
systems on these engines. The N54 engine has 2 underbody catalysts in addition
to the "near engine" catalysts
already in use from the N52.
The N51 engine, however, is a SULEV II compliant engine which
REMOVING AND INSTALLING/REPLACING INTAKE FILTER HOUSING (N52K)
Necessary preliminary tasks:
Switch off ignition
Lever out expansion rivets (1).
Press lock (2) and raise intake duct (3).
Detach intake duct (3) from air filter housing and remove.
Fig. 8: Identifying Expansion Rivets, Lock And Int