BMW Turbo Oil Leak
This bulletin applies to BMW 2, 3, 4 and 5 series vehicles with turbocharged B46/48 engines. If an oil leak is observed at the turbo oil return line connection, inspect the asbestos-free gasket. It may have been installed flipped upside down with the raised bead surface facing toward the turbo.
The asbestos-free gasket part number (P/N) 11 42 7 577 017 must be installed with the raised bead surface facing toward the oil return line. To repair the leak, replace the oil pipe outlet P/N 11 42 7 617 535, the asbestos-free gasket, and the O-ring P/N 11 42 8 604 872.
Example of correct gasket orientation with the gasket bead facing the return line. Don’t forget to also replace the O-ring.