The cause: The original plastic Disa valve components wear and often snap causing the symptoms noted above. The pin retaining the flap can also pop out entering the engine! The likely cause of the faults noted above and most common cause is the weak plastic components within the DISA valve unit vibrating together and wearing causing the flap to operate at the wrong times and eventually leading to destruction of the flap plate. The pieces of this flap can even enter the engine often causing severe engine damage; likewise the metal pin that holds the flap plate in position can vibrate loose and enter the engine. The solution: Fit our improved design billet aluminium flap kit, designed to never fail, save the cost of a replacement DISA valve which will only fail again. Using our kit the weak components of the DISA valve the flap and crank lever are replaced with our many times stronger billet aluminium parts, retained by our precision machined screw which tightly retains the two components together; eliminating wear and the need for the retaining pin which can enter the engine. Our part is completely redesigned to never fail- OEM clearances are reduced minimising vibrations in the part preventing any future failure. Our kit also includes a high temperature Viton 75 O-ring to make a good seal between the DISA unit and the manifold eliminating any air leaks. Vehicles Affected: BMW M54 2.2 &2.5 Liter Applications E36 2000-2002 Z3 2.5i Roadster E39 2000-2003 525i Touring E39 2000-2003 525i Sedan E46 2000-2004 320i Sedan E46 2000-2006 325Ci Coupe+M56 E46 2000-2006 325Ci Convertible E46 2000-2005 325i Touring E46 2000-2005 325i Sedan E46 1999-2004 325xi Sedan E46 1999-2005 325xi Touring E60 2002-2004 525i Sedan E83 2003-2006 X3 2.5i SUV E85 2002-2005 Z4 2.5i Roadster. BMW Part# : 11617544806 or 11617502269. Number Stamped on DISA Housing: 7544806 or 7502269.