Differentiating features:

WARNING: This page is about a different car, the 2002 BMW M Roadster, 2002 BMW M Coupe, 2001 BMW M Roadster, and 2001 BMW M Coupe. However, it is still accessible from the selected car via links, so may be relevant.

Conrod bolt with M11x1.25 thread
Bolt head: bihexagonal 12 mm A/F
Conrod bolt with M10x1.25 thread
Bolt head: Torx E12

Fig 1: Identifying Conrod Bolts

Courtesy of BMW OF NORTH AMERICA, INC.

CAUTION: The procedure for replacing the conrod bolts and the tightening specifications are different. Mixing up the procedure for replacing the conrods and conrod bolts and the tightening specifications will result in serious engine damage.

CAUTION: Note grinding stages on crankshaft. Refer to CRANKSHAFT AND BEARINGS .

NOTE: Classified conrod bearing shells color-coded "Yellow and Green" are installed in the model series.

The classification is removed when the conrod bearing shells are replaced.

Install conrod bearing shells (1) color-coded "Blue" in conrod at top.
Install conrod bearing shells (2) color-coded "Red" in conrod at top.

Install piston. Refer to 11 25 530 Removing and installing/replacing all pistons (S54) .

Fig 2: Installing Conrod Bearing Shells

Courtesy of BMW OF NORTH AMERICA, INC.