BMW (94-08) Air Filter Housing O-Ring (x1) GENUINE O-Ring - Air Filter Housing (79 X 6 mm) NOTE: z3 2.8 fits from 09/1998 PRODUCTION Date onward. NOTE: 325i/325ci fits M54 engine only. part# 13 71 1 720 540, see FITMENT CHART below under PRODUCT DESCRIPTION. Genuine BMW part, recently made: not been lying around.