Odd "Tinny" sound... Cant track it down

[Cbouts]

Ok, this is a long shot but I could definitely use a fresh "set of eyes" on this.

02’ M with 43,000 – Big 3 have been completed.

Here and there, I get a tin can sound from under (i think) the car. Generally, it’s under hard breaking but at MPact over the weekend it made the sound while accelerating. Sounds like a tin can is dragging on the ground for 4-5 seconds then goes away. there is nothing loose under the car. I thought it might be the brakes, but replaced the pads and rotors and checked all the dust shields… everything looks good… Almost seems like something is sliding and then hitting another moving part, maybe the fans up front? Any ideas?

Happy to answer any questions. Always appreciate the support.

[Slideways]

Do you have a video of the noise? Rear dust shield was my first guess, but you ruled that out.

[Cbouts]

no video but have thought about trying. its so sporadic which is part of the problem. I cant guarantee its not the dust shields but none of them are loose or touching the rotor. even checked all the bolts holding them on.

when it happens, its a pretty nasty sound. definitely not faint.

[ATB88]

Have you touched your headers or exhaust section 1 lately? This reminds me of after I installed euro headers: one of the sec 1 to header gaskets didn't seat properly, and while there was not an exhaust leak, the bolts while seeming tight, weren't holding the sec 1 where/how it needed to be. This caused an intermittent loud tin-can like rattle. Removed and re-mounted section 1 and it went away. Was pretty surprised that exhaust could rattle like that with all of the bolts tight! Anyway, worth a mention. Hope you find it!

[OEMaddict]

Is it a consistent scraping like noise or a tapping noise? I think I had a similar noise to this back when I first picked up my car.

[Cbouts]

Have you touched your headers or exhaust section 1 lately? This reminds me of after I installed euro headers: one of the sec 1 to header gaskets didn't seat properly, and while there was not an exhaust leak, the bolts while seeming tight, weren't holding the sec 1 where/how it needed to be. This caused an intermittent loud tin-can like rattle. Removed and re-mounted section 1 and it went away. Was pretty surprised that exhaust could rattle like that with all of the bolts tight! Anyway, worth a mention. Hope you find it!

Was actually just under the car and headers are fine. Never been off that I'm aware of. Heat shield was a little bit loose but shouldn't be the cause of the sound. It's not constant or over bumps. Generally only does it on hard braking and even then, its not every time.

QUOTE=OEMaddict;n49668]Is it a consistent scraping like noise or a tapping noise? I think I had a similar noise to this back when I first picked up my car.[/QUOTE]

Great question and i guess more of a grinding? My wife describes it as "dropping empty soda cans from under the car" lol. I will attempt to get video but might be a while...

[Speed Monkey]

While your sled is parked in a safe condition, slide underneath and grab each half shaft; if excessive play exists in the inner and outer CV joints, this may cause your intermittent sound. When the half shafts on my sled decided to pack it up, the first noise I heard sounded like a rock stuck between the brake rotor and the sheet metal shield behind the rotor. Like you say, it’s a distinct tinny sound. Good luck huntin’ down your problem.

[mrgizmo04]

When the rubber mounts start giving out that hold up section 2 of the exhaust, the pipe starts banging on the cross braces.

Parts 8 and 9 are what I'm talking about here: https://www.realoem.com/bmw/enUS/sho...diagId=18_0447

Sent from my SM-G950U using Tapatalk

[Cbouts]

When the rubber mounts start giving out that hold up section 2 of the exhaust, the pipe starts banging on the cross braces.

Parts 8 and 9 are what I'm talking about here: https://www.realoem.com/bmw/enUS/sho...diagId=18_0447

Sent from my SM-G950U using Tapatalk

Exhaust is solid. Normal movement even when i really pull/shake it.

Half shafts & CV Joints seem fine.

I believe it's coming from the front of the car. As always, really appreciate the help. Will update if we figure it out.

[Cbouts]

Lets see if this works. Here is a URL for a sound clip. Sound kicks in around 7 seconds. Might need to turn up your speakers.

https://voca.ro/4v5QR2RVPs7

Happens when i hit the brakes but i dont believe its FROM the brakes. Also, definitely coming from the front of the car.