Slackening the chain tensioner of cylinder bank 1

NOTE: RISK OF DAMAGE
Careless handling of tools and sharp-edged components.
Scratches, surface damage.

Protect working area.
Handle tools and components carefully.

NOTE: TECHNICAL INFORMATION
When the engine is stopped after the completion of trip, it may be necessary to run the electric fan. In rare cases, operation of the electric fan can last up to 11 min. This protects the components. In this case, replacing the electric fan will not remedy the problem!

Preliminary work

Refer to REMOVING THE COVER FOR THE CENTER ENGINE COMPARTMENT .
Refer to REMOVING BOTH FRONT-END STRUTS .
Refer to REMOVING FRONT CROSS CONNECTION (FRONT-END STRUT REMOVED) .
Refer to REMOVING THE REAR TOP CROSS CONNECTION .
Refer to REMOVING FAN COWL .
Refer to REMOVING THE FRONT RIGHT LOWER WHEEL ARCH COVER .
Refer to REMOVING THE LEFT FRONT BOTTOM WHEEL ARCH COVER .
Refer to REMOVING THE FRONT UNDERBODY PROTECTION OR FRONT THRUST FIELD .
Refer to REMOVING THE UNDERBODY PROTECTION OF THE STEERING GEAR AND THRUST FIELD RESPECTIVELY .
Refer to DRAINING THE COOLANT FOR THE LOW-TEMPERATURE COOLANT CIRCUIT .
Refer to REMOVING THE COOLANT EXPANSION TANK FOR THE LOW-TEMPERATURE COOLANT CIRCUIT (CHARGE AIR COOLER) .
Refer to REMOVING RIGHT CHARGE AIR COOLER .
Refer to PARTIALLY RELEASING THE GUIDE TUBE FOR THE OIL DIPSTICK .
Refer to REMOVING THE SEALING CAP ON THE CYLINDER HEAD OF THE CYLINDER BANK 1 .

NOTE: RISK OF DAMAGE
Damage to timing chain or timing chain drive.
Turning the engine without chain tensioner or special tool can result in damage to the timing chain and timing chain drive.

Always turn the engine with the chain tensioner or the special tool.

NOTE: TECHNICAL INFORMATION
Conduct the following operation with the assistance of a second person.

Make sure the chain drive is simultaneously loaded on the central bolt of the engine and on the VANOS exhaust central valve.
Observe the movement of the chain tensioner piston.

Perform the following steps simultaneously:
With a second person, keep the VANOS exhaust central valve under tension clockwise.
The VANOS exhaust central valve must not be twisted.

Courtesy of BMW OF NORTH AMERICA, INC.
Turn engine counter clockwise at central bolt (1).

Courtesy of BMW OF NORTH AMERICA, INC.

Slackening the hydraulic chain tensioner of cylinder bank 1
NOTE:
RISK OF DAMAGE
Damage to timing chain or timing chain drive.
Turning the engine without chain tensioner or special tool can result in damage to the timing chain and timing chain drive.
- Always turn the engine with the chain tensioner or the special tool.
Courtesy of BMW OF NORTH AMERICA, INC.
Position the special tool 0 491 012 (11 4 120) (3) in the bore and fasten the chain tensioner piston.
Make sure the chain drive is simultaneously relieved on the central bolt of the engine and on the VANOS exhaust central valve.
Perform the following steps simultaneously:
Relieve the chain drive clockwise at the central bolt.

Courtesy of BMW OF NORTH AMERICA, INC.
Relieve the chain drive counterclockwise at the VANOS exhaust central valve,

Courtesy of BMW OF NORTH AMERICA, INC.