11 25 530 Removing and installing/replacing all pistons

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2010 BMW 535xi, 2010 BMW 535i, 2009 BMW 535xi, 2009 BMW 535i, and 2008 BMW 535xi. However, it is still accessible from the selected car via links, so may be relevant.

Special tools required:

WARNING: Protective goggles must be worn when working on the piston pin circlip.

IMPORTANT:

If pistons, connecting rods and bearing shells are reused, they must be reinstalled in the same places.

Individual connecting rod replacement is not permitted; they are classified according to weight categories.

Connecting rods and connecting rod bearing caps are marked with the same pairing letters; mixing them up will result in engine damage.

Piston and gudgeon pins are paired and must not be fitted individually.

Necessary preliminary tasks:

Remove engine.
Mount engine on ASSEMBLY STAND .
Remove INTAKE AIR MANIFOLD .
Remove CYLINDER HEAD .
Remove engine oil sump.
Remove OIL PUMP .

NOTE: In event of heavy oil carbon residue:
Carefully remove oil carbon residue from cylinder wall.

NOTE: Illustrations show N46.

Fig 1: Locating Cylinder Wall

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Do not release screw (1).

OIL SPRAY NOZZLE (2) must not be maladjusted or bent.

If necessary, readjust (risk of damage ).

Fig 2: Identifying Screw And Oil Spray Nozzle

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Release connecting rod bolts (1).

Tightening torque, 11 24 1AZ .

Remove connecting rod bearing cap (2) in direction of arrow.

IMPORTANT: Connecting rods and connecting rod bearing caps are marked with the same pairing letters; mixing them up will result in engine damage.

Fig 3: Removing Conrod Bearing Cap

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Screw special tool 11 8 590 into base of connecting rod.

Press out connecting rod and piston to cylinder head side.

IMPORTANT: Risk of damage to oil spray nozzle.

Fig 4: Screwing Special Tool (11 8 590) Into Base Of Connecting Rod

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Preliminary work:

Clamp special tool 11 8 561 in a vice.

Secure piston (1) with connecting rod to special tool 11 8 561.

Fig 5: Securing Piston With Conrod To Special Tool (11 8 561)

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WARNING: Protective goggles must be worn for the next work step.

WARNING: Protective goggles must be worn.

To lever out piston circlip (1), support special tool 11 5 464 on piston (2).

Lever out piston circlip (1) with special tool 11 5 464 in direction of arrow.

Fig 6: Removing Piston Circlip Using Special Tool (11 5 464)

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If necessary, replace connecting rods.

IMPORTANT:

Connecting rods are divided into weight categories and are only available as a set.

Old and new connecting rods must not be installed in mixed combinations.

Fig 7: Identifying Connecting Rod

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Installation note:

The gudgeon pin must be able to be pressed through the liner by hand with little force and must not display any significant play.

Measure PISTON INSTALLATION CLEARANCE:

Measure piston diameter with micrometer at measuring point A from bottom edge of piston and offset at 90° to the axis of the piston pin.

Piston diameter at measuring point A.

Fig 8: Measuring Piston Diameter With Micrometer At Measuring Point A From Bottom Edge Of Piston

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Adjust micrometer to cylinder bore of engine block. Set internal caliper on micrometer to zero. Measure bottom, center and top of cylinder bore in direction of travel and direction of engine rotation.

Diameter of cylinder bore.

Piston installation clearance.

TOTAL PERMISSIBLE WEAR TOLERANCE .

If necessary, replace piston.

Fig 9: Measuring Cylinder Bore Diameter

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WARNING: Protective goggles must be worn.

IMPORTANT:

The opening of the piston pin circlip must be installed in the 6 o'clock position on the piston.

Risk of damage!

Insert piston circlip (2) into groove of special tool 11 8 562 .

Bring piston circlip (2) into assembly position (1).

Fig 10: Inserting Piston Circlip Into Groove Of Special Tool (11 8 562)

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WARNING: Protective goggles must be worn.

Slide special tool 11 8 563 up to piston pin circlip (2)

Special tools 11 8 562 and 11 8 563 are prepared.

Fig 11: Identifying Special Tools (11 8 562) And (11 8 563)

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WARNING: Protective goggles must be worn.

Cutout on special tool 11 8 562 must point to piston crown; only then can special tool 11 8 563 be correctly fitted.

When special tools 11 8 562 and 11 8 563 are correctly positioned, the piston pin circlip must be driven in with a plastic hammer in the direction of the arrow.

NOTE: See illustration.

Fig 12: Removing Piston Pin Using Special Tools

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Piston pin circlip is correctly installed when opening (1) points downwards.

Fig 13: Identifying Piston Pin Circlip

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NOTE: B 30.

Instal all PISTON RINGS .

Install all BEARING SHELLS .

Coat piston and piston rings with oil.

Pre-install piston (2) in special tool 11 8 141.

Screw on special tool 11 8 590 in connecting rod (2).

Fig 14: Identifying Special Tool (11 8 141) And (11 8 590)

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Installation note:

Check protective lugs (1) on special tool 11 8 590 for correct position and damage.

Insert piston with connecting rod in cylinder.

IMPORTANT: Risk of damage to oil spray nozzle.
Danger of piston ring failure.
Press in piston in direction of arrow with finger pressure only, do not drive in.

Insert piston so that arrow on piston crown points to camshaft drive.

Press in piston (1) with special tool 11 8 141.

Fig 15: Pressing Piston Using Special Tool (11 8 141)