Spark Plug: Service and Repair

Replacing All Spark Plugs (M73)

Switch off ignition.







Cylinder bank 1-6:
Press interlock (2) and remove connector (1).







Open clips (1).
Unfasten hose clip (2) from auxiliary hose for air pump.
Disconnect plug-in connection (3).
Unfasten hose clip (4).
Remove upper section of suction filter housing with mass air flow sensor.







Cylinder bank 7-12:
Open clips (1).
Unfasten hose clip (2).
Disconnect plug-in connection (3).
Remove upper section of suction filter housing with mass air flow sensor.







Disconnect plug connections (1 and 2) from heating valve.







Pull heating valves (1) out of rubber mounts (2) and lay below engine.







Release cable ties (1) and lay air hose (2) below engine.







Cylinder 1-8
Use special tool 12 7 131 (extension) and special tool 12 1 171.







Cylinder 1-8

Installation:
Tighten down spark plug with special tool 12 1 171 and special tool 12 7 131 (extension), special tool 12 1 200 (torque limiter).







Cylinder 9-12
Use special tool 12 7 132 (extension) and special tool 12 1 171.







Cylinder 9-12

Installation:
Tighten down spark plug with special tool 12 1 171 and special tool 12 7 132 (extension), special tool 12 1 200 (torque limiter).