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TommyFisch

BMW Z4 Exhaust Flap Problems: Causes and Solutions

Loud engine when cold

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Fault stored

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Loud exhaust

Hi there! My 2008 BMW Z4 has been acting up lately. The exhaust is much louder than normal, especially during cold starts, and I can't control the exhaust flaps anymore. I've got some error codes stored in the system too. I suspect it's related to faulty exhaust flaps, but I'd like to hear from others who've dealt with similar issues. Has anyone experienced this and got it fixed? What did the repair involve? Any help would be appreciated. Thanks

4 comment(s)


JoKle91

Hey there! I had a similar issue with my 2006 BMW 330i last winter, and yes, it was the exhaust flap. The symptoms were exactly like yours, super loud exhaust and no control over the flaps. Initially, I thought it might be something else, but my mechanic confirmed it was a defective exhaust flap actuator. Got it fixed at my regular workshop, ended up costing me around 190 Euro total. They had to replace the actuator and reset the system. After that, everything went back to normal, and the annoying loud noise disappeared. What's your mileage on the Z4? Also, which engine variant do you have? This could help me share more specific details about what to expect during the repair. Have you noticed any other symptoms besides the loud exhaust?

TommyFisch (Author)

Thanks for sharing your experience! My Z4 just hit 157454 KM and had its last service about 3 months ago. I've got the 3.0i gasoline engine. The loud exhaust is definitely the main issue, but I've also noticed a slight rattling sound when idling. I'll probably take it to my mechanic then, seems like it might be the same actuator problem you had. Did they have to order the part specially, or was it something they had in stock? Just trying to get an idea of how long I might be without the car.

JoKle91

Hey again! Yeah, sounds exactly like what I dealt with. The rattling at idle is another telltale sign, had that too. My workshop had to order the actuator specifically for my car, took about 3-4 days to arrive. But the actual repair only took them a few hours once they had the part. Just to give you a heads up, with your Z4 having similar mileage to what my 330i had when this happened (mine was around 160000 KM), you might want to have them check the exhaust flap linkage too while they're at it. Sometimes the linkage can get worn out or corroded, and if they don't replace that along with the actuator, you might end up with the same issue again in a few months. When they fixed mine, they actually showed me the old actuator, it was pretty messed up from moisture and heat cycles. Your symptoms are so similar, I'd bet money it's the same issue. The good news is that once it's fixed, it's usually good for quite a while. Mine's been running perfectly for over a year now. Let me know how it goes when you get it checked out. Curious to hear if it's the same problem!

TommyFisch (Author)

Thanks for all that detailed info! I'll definitely ask them to check both the actuator and the linkage when I take it in. That's really helpful knowing about the potential linkage issue, would hate to have to deal with this again in a few months. I've already called my mechanic and they're able to take a look at it next week. They'll order the parts once they confirm the diagnosis, but at least I know what to expect now. Really appreciate you sharing your experience with the 330i, it's made me feel a lot better about the whole situation. I'll make sure to post an update once it's all sorted. Thanks again for all your help!

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