2011 Z4 35iS Rattling Exhaust

[Marky264]

Hi Everyone,

Need some advice, So after 4 Months of owning My '61 Plate Z4 35iS I've since had the Fuel Pump changed due to the Car taking over 7 Seconds of cranking.

After that issue had been rectified I believed I would be trouble free for at least a year. The other morning I started up my car and I could hear an Exhaust Rattle on cold start up, It's very noticeable as I notice any small difference to how the car sounds as It's my daily driver to and from work.

The rattle is coming from the Exhaust and the exhaust sounds a lot louder than It was before in Comfort mode It sounds like a flap is stuck or something as It sounds a lot different now when driving, Louder for sure but not subtle anymore,

The rattle happens when you pull away at slow speeds up to 20 MPH or when you put a tiny amount of pressure on the accelerator pedal and quite frankly sounds awful and that It's an old car about to break to other people.

As I'm understanding the warmer the car part of the exhaust expands thus filling that rattle but I don't want It sounding like this every day,

Any advice on what I should do? I was going to call another BMW Service centre in the morning to get It booked in as I'm sure whatever needs to be done will get done under warranty like the Fuel Pump was.

Just didn't expect to get issues like these 4 Months Into owning it. It's only done 38K Miles so I'm Just getting concerned It could be something more.

I also Read on the AUC Paper work that there was a Sump Leak/Weeping Sump that was replaced and fixed at some point before the car was sold to me by BMW Boston Listers, Could this have a relation to it? The Technician who worked on my car last time for the Fuel Pump told me that he noticed It was still weeping and that at some point to bring It back to have a further look.

I read on similar articles that the 335i had something like this and that a Fix was for BMW to cut off the back box or something along those lines and replace and that it was a Vacuum Actuator issue?

Anyways any advice would be much appreciated!

[NoQuarter]

Sounds like the exhaust flap is rattling.

It is in the rear, under the car near the exhaust tip.

[Geodoc]

Could be the infamous wastegate rattle. I though my problem was the exhaust flap but turned out to be turbo wastegates see https://e89.zpost.com/forums/showthread.php?t=1040575