Team-BHP - Rattling noise from the exhaust of my BMW 328i

Hi everyone,

I needed some of you to weigh in on a a problem I'm facing with my BMW 328i. My car suddenly started making a rather loud rattling noise coming from the end of the exhaust pipe. The noise starts as soon as I start the engine, hot or cold, and continues while driving. It sounds exactly like this:

https://www.youtube.com/watch?time_c...&v=WehoZwVDqXw

Thanks to the good folks of the world wide web, I figured out the problem. The noise is being caused by the exhaust flap. My car has an electronic flap within the exhaust pipe that opens and and closes depending whether the car is idling or being driven. As I understand, the actuator is broken, the flap has come loose and is making the rattling noise.

I went to the BMW service center and they identified the exact same problem. Their solution is to replace the entire exhaust set up which will cost me about 70k. Also, the part has to be imported from Germany and will take 3 weeks!!

I also went to a local workshop chain which goes by the name of GoMechanic (https://gomechanic.in/luxury-car-enquiry/bmw). They claim to have experienced mechanics, well verse with German cars. They also identified the same problem and said they could cut open the exhaust pipe, fix the flap and weld it back. This is likely to cost about 10-12k. I am very apprehensive about having the exhaust pipe cut open.

Additionally, reading on the internet, it seems there is a cheap and easy fix by installing a new spring/ fixing bow (https://parts.bmwnorthwest.com/p/BMW...307620323.html) and takes no more than 20 minutes.

I am afraid I am not receiving the most sound advice on this from the BMW workshop or this local workshop. I would really really appreciate if some of you could share some thoughts or suggest another mechanics/ workshop in South Delhi/ Gurgaon/ Noida where I can get some honest inputs.

Thanks a ton for reading and thank you in advance!

UDit

^^

The flap seems to just improve the residence time of the exhaust in the cat con for better conversion of CO; can't think of any other reason why this damper is given.

Anyways, if the bow spring connecting the actuator to the flap is broken, and thus the culprit, it can be replaced from outside; just need to lower the exhaust assembly from its mounting a bit to create access to replace the bow spring.

I suggest you take the car to a competent FNG in Mumbai and get this done.

Here are some pics of the actuator assembly; kindly reconfirm if the same applies to the 328i.

Some models have vacuum actuators while some are electronic.

Quote:

Originally Posted by vigsom (Post 4636571)

^^

Anyways, if the bow spring connecting the actuator to the flap is broken, and thus the culprit,

I believe that is the case. I am no expert on the issue but that is my understanding based on what I have read online and the feedback I have received from BMW as well as the local workshop.

I am not in Mumbai. I have relocated to New Delhi. I was hoping someone could recommend a trustworthy FNG in Delhi NCR where I could take care of this rattle without having to cut open the exhaust pipe.

Quote:

Originally Posted by HMV (Post 4636665)

EDIT: Sorry, It was only later that i realised that, it was just an illustrative video and not exact one!

Yes, you're right. The YouTube video demonstrating the sound is just for reference and is not a video of my actual car.

Quote:

Originally Posted by vigsom (Post 4636762)

Please check this place out; it has been recommended in the directory of FNGs in Delhi.

There are other places in the directory too which you might want to evaluate.

https://www.team-bhp.com/forum/delhi...new-delhi.html

Thanks a ton! This is very helpful. I had looked at the directory for Delhi NCR but somehow missed this. I will reach out to these guys tomorrow considering today is Eid. On that note, Eid Mubarak to everyone!