This is a common problem with these cars. From what I can tell, this is purely an annoyance rather than a mechnical breakdown. The value of the ~$100 “fix” is for you to decide. I think it’s totally worth it. This particular car had a slight rattle from day 1 – but it quickly went away after a few seconds of idle. It’s gotten progressively worse over the years until recently when the rattle became really bad — as you can hear. The rattle does go away, for the most part, once the car is 100% warmed up and you’ve been driving. This “repair kit” is very easy to install. Because of space, the most difficult part is snapping the stainless steel clip on the actuator arm. Small hands are welcomed. If the exhaust were off the car — or lowered — you could do it with your eyes closed.
Car: 2011 BMW 335i XDrive Coupe, Automatic (Factory/Stock – no engine/exhaust modifications)
Exhaust Rattle Repair Kit – E92
Part Number: AGA-ER-E92
Problem: You hear a rattle from the rear of your vehicle, come to find out the exhaust butterfly valve is loose causing the rattle noise. The valve is only available with the complete exhaust; the exhaust is very costly and requires a fair amount of labor to replace.
Solution: The AGA Exhaust Rattle Repair kit E92. This kit has a silicon bronze housing that supports the shaft with an internal spring that applies pressure on the shaft eliminating the rattle noise from the exhaust flap. In addition, there is a spring loaded stainless steel clip that provides a small amount of tension between the actuator arm and exhaust flap arm; this eliminates any rattle from the loose/worn arm.
Benefit: The AGA Exhaust Rattle Repair kit E92 eliminates the need to buy an expensive exhaust and the labor to replace it. The exhaust flap remains operational and you continue getting the increased torque and top end power from the exhaust flap function. The kit installs easily without any special tools.