BMW 3-Series and 4-Series Forum (F30 / F32) | F30POST
>
Weird noise coming from downpipe area when driving cold.
| 10-20-2022, 01:52 PM | #1 |
|
Private
 6
Rep 60
Posts |
Weird noise coming from downpipe area when driving cold.
2018 340i Stage 2 aftermarket downpipe. Whenever I get in the car and start driving it, theres a weird, rattily ass noise coming from my downpipe area and I have no idea what it is. Even after a long drive, I leave the car to say go into a place for 30+ minutes, and comeback and its still there, despite the engine being warm. Below is a video, anyone know if this is a cause for concern?
https://youtube.com/shorts/ZDDxGoTdpvo?feature=share |
| 10-20-2022, 06:01 PM | #3 |
|
Major General
 
4483
Rep 7,742
Posts |
The video is on the park brake cable clip, which is easy to diagnose. If the problem happens while stationary that is definitely not it. Did it happen after DP install? Did you check the vbands and position of the exhaust to make sure it didint shift and start rattling on something?
|
|
Appreciate
0
|
| 10-20-2022, 06:44 PM | #4 |
|
Major General
1936
Rep 5,320
Posts |
Sounds like your DP is rubbing the frame or the mid-pipe is rubbing the cross member. You'd need to loosen the bolts, and twist it so that there is space for it to move when the engine rocks under load.
|
|
Appreciate
0
|
| 10-24-2022, 05:58 PM | #5 |
|
New Member
8
Rep 10
Posts |
I agree with Wires, I had this same problem with my 335. It was my downstream o2 sensor tapping against the firewall. I twisted it into the best position, removed the sensor, and used a plastic deadblow hammer to beat the heat shielding back by about half an inch. No more noise after that.
|
|
Appreciate
0
|
| 10-25-2022, 06:30 AM | #6 |
|
Brigadier General
2047
Rep 4,111
Posts |
Ever since I had my aftermarket DP installed, I occasionally get horrible rattling sound, BUT.... notice this... ONLY in slushy/snowy weather in the winter, when I press the throttle just a little!!! Very loud and sounding as if a piece of plastic or sheet-metal goes into heavy resonance!
It is speed independent and again - ONLY in slush/snow. I have had the car/echaust inspected where they previously installed the DP - they found nothing which could be causing it. And it is mysterious - how/where would slush/snow accumulate and not melt to water instantly from the heat of the exhaust!? The noise started the first winter after DP upgrade, had it again the second. Initially I thought there is something wrong with the front-right wheel as that's where the sound seems to be coming from.... which incidentally is also where the DP is 
__________________
"Large increases in cost with questionable increases in performance can be tolerated only in cars and women."
|
|
Appreciate
0
|
Post Reply |
| Bookmarks |
|
|
