Reliable bleeder/drain screw for coolant expansion tanks, designed as a directfit replacement for part number 17111712788. This compact screw with rubber Oring restores a secure seal and provides a controlled vent/drain point on compatible BMW expansion tanks. Why you need it Eliminates coolant leaks and air pockets caused by damaged, stripped, or missing bleeder screws. Restores proper coolant system bleeding and draining for reliable engine cooling performance. Simple replacement prevents recurring coolant loss and avoids overheating or poor heater performance. Key features and attributes Compatibility: Directfit replacement for BMW 17111712788. Compatible with E46, E92, E90, E36, and E39 expansion tanks as specified. Function: Acts as both a bleeder screw to release trapped air during coolant fills and a drain screw for controlled coolant removal during maintenance. Seal: Supplied with a rubber Oring to ensure a tight, leakresistant connection at the tank port. Construction: Precisionmade screw designed for consistent thread engagement and reliable sealing. (Includes rubber Oring as specified.) Installation: Straightforward swap using common hand tools; designed for direct replacement without modification. Performance benefits Restores proper bleeding to remove air pockets and reduce the risk of overheating. Provides a secure drain point for routine coolant changes, flushing, or winter service. Longerlasting seal with a fresh Oring versus worn factory parts. Typical applications Cooling system maintenance: the screw when flushing or refilling coolant to ensure a reliable bleed/drain point and a proper seal. and replacement: Swap a stripped or leaking bleeder/drain screw on E46, E92, E90, E36, or E39 expansion tanks to stop coolant loss and restore system integrity. Preventive maintenance: Install a screw and Oring during scheduled coolant service to avoid future leaks and maintain consistent cooling performance. Installation notes Inspect mating threads and the tank port for damage before installation. the rubber Oring if worn or deformed to ensure a leak seal. Tighten securely but avoid excessive torque to prevent thread damage. Compatible models and part reference Fits BMW expansion tanks using part number 17111712788. Compatible model families: E46, E92, E90, E36, E39. This replacement bleeder/drain screw supplies a simple, reliable fix to restore proper coolant venting and draining for the listed BMW models.