Have you deleted your mechanical fan? This Genuine BMW part is designed to cover and protect the water pump threads which are left bare when the fan clutch is removed. The fan clutch delete nut (BMW calls it a screw plug) is reverse threaded, and provides a "finished" look to your mechanical fan deleted engine bay.
BMW Part Number: 11511310640 11 53 1 310 640 11-53-1-310-640
Fits:
- 1996-2002 Z3 (All)
- 1993-1999 E36
- 1986-1991 E30 M3
- May be additional BMW Applications