Replacement: Replacing all pistons

CAUTION: Component with heavyweight.
Injury hazard!

Note component's center of gravity.
Support component using a jack.
Secure component against falling off the jack.

CAUTION: On releasing high pressure line, fuel may emerge at high speed.
Injury hazard!

Wear suitable personal protective equipment.
Before performing any installation work, allow cooling system to cool down to less than 40°C
Note warnings on cylinder head cover.

NOTE: TECHNICAL INFORMATION
For the following engine, the piston rings must be replaced in combination with new pistons.
The following repair instructions provide instructions for the installation and removal, and also the replacement, of the piston with the piston rings.

NOTE: TECHNICAL INFORMATION
Collect and dispose of emerging fluids. Observe country-specific waste disposal regulations.

Preliminary work

Refer to REMOVING ENGINE .
Refer to INSTALLING THE ENGINE ON THE ASSEMBLY STAND .
Refer to RELEASING THE OIL DRAIN PLUG
Refer to TIGHTENING THE OIL DRAIN PLUG
Refer to REMOVING ALL SPARK PLUGS .
Refer to REMOVING THE HIGH PRESSURE LINE BETWEEN THE HIGH PRESSURE PUMP AND THE RAIL .
Refer to REMOVING HIGH PRESSURE PUMP .
Refer to REMOVING THE RAIL WITH INJECTORS .
Refer to REMOVING BOTH ACTUATORS .
Refer to REMOVING THE CYLINDER HEAD COVER .
Refer to REMOVING TANK VENT VALVE .
Refer to REMOVING THE INTAKE PLENUM .
Refer to REMOVING THE HEAT SHIELD AT THE CYLINDER HEAD .
Refer to REMOVING THE OIL RETURN LINE FOR THE EXHAUST TURBOCHARGER .
Refer to REMOVING THE COOLANT RETURN LINE FOR THE EXHAUST TURBOCHARGER .
Refer to REMOVING THE COOLANT FEED LINE FOR THE EXHAUST GAS TURBOCHARGER .
Refer to BLOCKING ENGINE IN TDC FIRING POSITION .
Refer to REMOVING CHAIN TENSIONER .
Refer to RELEASING THE VANOS CENTRAL VALVE OF THE INTAKE ADJUSTER .
Refer to RELEASING VANOS CENTRAL VALVE OF THE EXHAUST CAMSHAFT ADJUSTER .
Refer to REMOVING THE VANOS CENTRAL VALVE OF THE INTAKE ADJUSTER .
Refer to REMOVING THE VANOS CENTRAL VALVE OF THE EXHAUST CAMSHAFT ADJUSTER .
Refer to REMOVING INTAKE ADJUSTER .
Refer to REMOVING EXHAUST CAMSHAFT ADJUSTER .
Refer to REMOVING THE TEST GAUGES FOR SECURING THE CAMSHAFTS .
Refer to REMOVING THE CYLINDER HEAD .
Refer to REMOVING THE CYLINDER HEAD GASKET .
Refer to REMOVING THE ACOUSTIC COVER OF THE OIL SUMP .
Refer to REMOVING FLYWHEEL .
Refer to REMOVING OIL SUMP .
Refer to REMOVING OIL VACUUM PUMP .
Refer to REMOVING THE OIL DEFLECTOR .
Refer to REMOVING ALL PISTONS WITH CONNECTING ROD .

NOTE: TECHNICAL INFORMATION
Wear safety goggles.

NOTE: The description is for one component only. The procedure is identical for all further components.

Use the special tools 2 455 002, 2410 685 and 2 447 297 to remove the piston from the connecting rod.

Courtesy of BMW OF NORTH AMERICA, INC.
CAUTION:
Piston pin snap ring with preload.
Injury hazard!
- The use of the specified special tool for the disassembly or installation is mandatory
- Wear safety goggles.
Use the special tool 2 447 297 to remove the piston pin snap ring.
Insert the flat side (3) of the special tool 2 447 297 in the groove (4).
Use the curved side (2) to grip and remove the piston pin snap ring (1).

Courtesy of BMW OF NORTH AMERICA, INC.

Check

NOTE: TECHNICAL INFORMATION
Piston and piston pin are matched to each other.
Always install piston and piston pin together and do not switch by mistake.

Courtesy of BMW OF NORTH AMERICA, INC.
Check whether the piston pin (1) has noticeable play in the piston.
Check whether the piston pin (1) can be removed without excessive force.

Result

» The piston pin (1) can only be removed with difficulty or the piston pin (1) has noticeable play.

Measure
Replace the piston (2) and the piston pin (1).
Parts: Piston, piston pin

To replace the piston, the piston pin length must be determined.

Courtesy of BMW OF NORTH AMERICA, INC.

Engine	Piston pin length	Pistons
B38M1 ECE	12x55 mm	8 678 931
B38M1 ECE	12.5X55 mm	8 678 931
B38M1 ECE	12X51 mm	9 494 399
B48M1 ECE	12x55 mm	8 678 931
B48M1 ECE	12.5X55 mm	8 678 931
B48M1 ECE	12X51 mm	9 494 399
B38M1 CN	12X55 mm	8 678 931
B38M1 CN	12.5X55 mm	8 678 931
B38M1 CN	12X52 mm	8 681 079
B48M1 CN	12X55 mm	8 678 931
B48M1 CN	12.5X55 mm	8 678 931
B48M1 CN	12X52 mm	8 681 079
B48O1 ECE+CN	12X55 mm	8 678 934
B48O1 ECE+CN	12.5X55 mm	8 678 934
B48T1 ECE+CN	12.5X59 mm	9 488 343

NOTE: TECHNICAL INFORMATION
Piston and piston pin are matched to each other.
Always install piston and piston pin together and do not switch by mistake.

Install new piston pins (1) in the new piston (2) and the connecting rod (3).

Courtesy of BMW OF NORTH AMERICA, INC.
CAUTION:
Piston pin snap ring with preload.
Injury hazard!
- The use of the specified special tool for the disassembly or installation is mandatory.
- Wear safety goggles.
Courtesy of BMW OF NORTH AMERICA, INC.
Position the piston pin snap ring (1).
The opening (mark) of the piston pin snap ring must point towards the piston crown (2).
Preload the piston pin snap ring (1) with your thumb.
Press the piston pin snap ring simultaneously with the special tools 2 410 685 and 2 455 002 in the piston.
Add the special tool 2 410 685 in a rotating manner and press the piston pin snap ring completely into the piston.

Courtesy of BMW OF NORTH AMERICA, INC.
Check whether the piston pin snap ring (1) fits correctly in the groove (2).
Check whether the opening (mark) of the piston pin snap ring points towards the piston crown (3).

Courtesy of BMW OF NORTH AMERICA, INC.

Follow-up work

Refer to MEASURING A CYLINDER .
Refer to INSTALLING ALL PISTONS WITH CONNECTING ROD .
Refer to INSTALLING THE OIL DEFLECTOR .
Refer to INSTALLING THE OIL VACUUM PUMP .
Refer to REFITTING ENGINE OIL PAN .
Refer to INSTALLING THE FLYWHEEL .
Refer to INSTALLING THE ACOUSTIC COVER FOR THE OIL SUMP .
Refer to BLOCKING THE CRANKSHAFT IN THE TDC FIRING POSITION OF CYLINDER 1 .
Refer to SEALING THE OIL DUCT .
Refer to CLEANING SEALING SURFACES .
Refer to REPLACING CYLINDER HEAD GASKET .
Refer to INSTALLING THE CYLINDER HEAD .
Refer to ADJUSTING THE CAMSHAFTS WITH THE SPECIAL TOOL .
Refer to INSTALLING EXHAUST CAMSHAFT ADJUSTER .
Refer to INSTALLING THE VANOS CENTRAL VALVE OF THE EXHAUST CAMSHAFT ADJUSTER .
Refer to INSTALLING THE INTAKE ADJUSTER .
Refer to INSTALLING THE VANOS CENTRAL VALVE OF THE INTAKE ADJUSTER .
Refer to PRE-TENSIONING THE TIMING CHAIN WITH THE SPECIAL TOOL .
Refer to TIGHTENING THE VANOS CENTRAL VALVE OF THE EXHAUST CAMSHAFT ADJUSTER .
Refer to TIGHTENING THE VANOS CENTRAL VALVE OF THE INTAKE ADJUSTER .
Refer to DISASSEMBLING ALL SPECIAL TOOLS .
Refer to INSTALLING CHAIN TENSIONER .
Refer to INSTALLING THE HEAT SHIELD ON THE CYLINDER HEAD .
Refer to CHECKING THE TIMINGS OF THE CAMSHAFT .
Refer to INSTALLING THE OIL RETURN LINE FOR THE EXHAUST TURBOCHARGER .
Refer to INSTALLING THE COOLANT RETURN LINE FOR THE EXHAUST TURBOCHARGER .
Refer to INSTALLING COOLANT FEED LINE FOR EXHAUST TURBOCHARGER .
Refer to INSTALLING CYLINDER HEAD COVER .
Refer to INSTALLING BOTH ACTUATORS .
Refer to PREPARING THE INJECTORS FOR INSTALLATION .
Refer to INSTALLING THE RAIL WITH INJECTORS .
Refer to INSTALLING HIGH PRESSURE PUMP .
Refer to INSTALLING THE HIGH-PRESSURE LINE BETWEEN THE HIGH-PRESSURE PUMP AND THE HIGH-PRESSURE RAIL .
Refer to INSTALLING ALL SPARK PLUGS .
Refer to INSTALLING INTAKE PLENUM .
Refer to INSTALLING THE TANK VENT VALVE .
Refer to REMOVING THE OIL FILLER CAP
Refer to TOPPING UP THE MOTOR OIL
Refer to INSTALLING THE OIL FILLER CAP
Refer to REMOVING THE ENGINE FROM ASSEMBLY JIG .
Refer to INSTALLING ENGINE .