11 25 671 Replacing piston rings on all pistons (M52 / S52 / M52TU / M54 / M56)

WARNING: This page does not describe the selected car, but rather 33 other vehicles, including the 2006 BMW 325Ci, 2005 BMW 325xi, 2005 BMW 325i, 2005 BMW 325Ci, and 2004 BMW 325xi. However, it is still accessible from the selected car via links, so may be relevant.

(piston removed)

Remove piston rings with a piston-ring compressing pliers.

NOTE: It might not be possible to find the identification on used piston rings.

Put aside piston rings in correct sequence and installation position.

Only install new pistons in conjunction with new piston rings.

Fig 1: Installing New Pistons

Courtesy of BMW OF NORTH AMERICA, INC.

Installation:

Install piston rings with "TOP" to piston top.

Plain compression ring
Stepped compression ring "Top"
Slotted oil ring with hose spring clip

Fig 2: Identifying Piston Rings
Courtesy of BMW OF NORTH AMERICA, INC.

Measure axial play.

Fig 3: Measuring Axial Play

Courtesy of BMW OF NORTH AMERICA, INC.

Measure end clearance.

Fig 4: Measuring End Clearance

Courtesy of BMW OF NORTH AMERICA, INC.