Crazy rattles under my car?

[M3 Number 86]

So tonight I drive home and when I get into my spot as I creep forward I hear some rattling. I try to replicate it and do it by going slowly back and forth. I thought it was exhaust rattle.

Being disturbed by it I went back out a little later and gave it a pull on the highway and exited. Then at the red light it was rattling just sitting there.

This has to be some sort of loose bolt no? I have no idea what did bearings sound like but this is an it loud for that. Guessing engine should have blown if it was.

First video is at the red light. Second video my phone is under the car and I'm lightly pressing the gas with my hand.

[roastbeef]

thats an odd sound. after being under the car for almost two days, i'm thinking it could be a lot of things. i'd start with checking all of the mounts for the xpipe. more specifically, the mount right behind where the second set of O2 sensors are.

[M3 Number 86]

Originally Posted by roastbeef

thats an odd sound. after being under the car for almost two days, i'm thinking it could be a lot of things. i'd start with checking all of the mounts for the xpipe. more specifically, the mount right behind where the second set of O2 sensors are.

I don't think I have those lol.

Actually I'll check. You might be right. Those aren't bolted to the xpipe. But maybe the nut on there got loose. Hmmm.

[roastbeef]

yea there are two bolts that connect to an arched arm that is about 1.5' long. i think it comes off the transmission or something, but it goes to two rings that help support the xpipe. i could see one of those bolts coming out and the arm of that brace vibrating against the bracket.

[M3 Number 86]

Originally Posted by roastbeef

yea there are two bolts that connect to an arched arm that is about 1.5' long. i think it comes off the transmission or something, but it goes to two rings that help support the xpipe. i could see one of those bolts coming out and the arm of that brace vibrating against the bracket.

It sounds like it's in front of that section though.

[roastbeef]

like ahead of the headers? the brackets i'm talking about are probably right below your feet as you are seated in the car.

[M3 Number 86]

Originally Posted by roastbeef

like ahead of the headers? the brackets i'm talking about are probably right below your feet as you are seated in the car.

I'm hoping it's just something that came loose. But as you can tell it's pretty damn loud. Scared to drive it and will have to tow to my shop. All over what is prob something stuck somewhere. I hope.

[roastbeef]

i don't think you need to tow it. it doesn't go up with rpm, right? if it doesn't, its not driveline and just something rubbing. don't sweat it.

[M3 Number 86]

Sounds like this doesn't it? One too many track days with low ps fluid?