BMW part number 18111723541 is a 45mm asbestos-free exhaust gasket/seal ring. This fiber or compressed mesh crush ring seals major downstream plumbing connections, commonly seating the catalytic converter piping into the center resonator or rear muffler sections. This part number frequently cross-references or swaps interchangeably with BMW part numbers 18111723533, 18101719350, and 18111178222. This 45mm sealing ring is exceptionally common across several major BMW chassis from 1977 to 1995, sealing midsection pipes for standard M20 inline-6 layouts and larger M30 inline-6 premium models:
3 Series (E30 Generation)
- 325i / 325is / 325ix (All-Wheel-Drive): 1987 – 1991
- (Note: Also carries over onto standard E30 325i Base Convertibles up through 1993)
5 Series (E28 & E34 Generations)
- 528e (M20 2.7L Efficiency engine): 1982 – 1988
- 535i / 535is (M30 3.4L engine): 1985 – 1988
- 525i (Early single-cam M20 2.5L engine): 1989 – 1990
- 535i (E34 layout with M30 engine): 1989 – 1993
6 Series & 7 Series (E23, E24, & E32 Generations)
- 633CSi / 635CSi / L7 (M30 big-bore engines): 1977 – 1989
- 733i / 735i (E23 Generation): 1978 – 1986
- 735i / 735iL (E32 Generation): 1987 – 1992
