2011 E90 M3 Knocking/Clashing noise

[iwantanm3]

Hey guys. I've been hearing this noise from my E90 M3 and I thought I'd post about it on here to try and get some opinions on it.

I've had this car for roughly 6 months. The car spent most of its life out here in the mid-west, started out in Indiana and is now with me in Champaign/Chicago, Illinois. I left the car in December for three weeks and came back to a semi-rough startup, but nothing too bad. I drive the car with immaculate care. I don't drive it rough often, but when I do it is 5-10 mins after everything is warm.

Starting early February, I started hearing this weird clashing/knocking noise from the lower part of the engine bay. I could only hear it when I put my head down near the left side of the engine bay, and it sent me on a frantic research. I watched too many videos on the rod bearing noise and I deduced that the noise wasn't the infamous rod bearing knock. To be completely safe, I took an oil sample from my oil change and sent it to Blackstone. I stopped driving the car for a few weeks until I got the report back and the report stated that my car didn't have rod bearing issues. My mechanic friend, however, was certain when we were doing the oil change that I was definitely spinning bearings.

I can't seem to find out what this sound is. It has become louder and louder as the time has passed. The noise also started coming out of the front passenger side wheel well as well. It has become so loud now that you could easily hear this sound if you're standing on the passenger side of the car. I think it could be an exhaust leak somewhere, but I can't be sure. I've kept looking for people with the same issue, but I haven't found anything so far. I'm currently busy with work, so I'll try my best to post a video of this later on in the day.

Symptoms:
-The noise is always heard every time I start the car at idle (Cold).
-The noise leaves when the cold start ends and the RPM slightly lifts up at the end.
-The noise can be heard when the car is less than 2000 RPM and warm, I've heard the noise with the windows down when creeping through a parking garage or through tight spacing with walls.


Please let me know what you think this is, a video will come tonight. I've attached the Blackstone below.

View post on imgur.com

[iwantanm3]

Could it be Vanos?

[R3dliner]

Just a FYI on LCI cars like yourself Blackstone is meaningless from the material changes to aluminum/tin.

Video would probably help.

[msan]

Originally Posted by R3dliner

Just a FYI on LCI cars like yourself Blackstone is meaningless from the material changes to aluminum/tin.

Video would probably help.

I agree blackstone is meaningless in this situation

[eatsleepboost]

Originally Posted by R3dliner

Just a FYI on LCI cars like yourself Blackstone is meaningless from the material changes to aluminum/tin.

Video would probably help.

The 088-089 bearings were used until mid 10 so even if you have an 11 like myself, they may still be the old style. My build date is 4/1/10 so I have the original lead copper design.

Yea a video is needed though.

[iwantanm3]

Dearest friends of the M3 community, I put the videos up here. I researched for the past few hours just meaninglessly scrolling through forums of cars, not just M3s, with this sound. It kind of seems like bad injectors or something. The video is posted below, however, it doesn't really capture how extreme the situation is. If you watch the full video, the sound does disappear after cold start cycle ends.

https://photos.app.goo.gl/HtNaNxoMyen3tFTg1

[iwantanm3]

Originally Posted by eatsleepboost

The 088-089 bearings were used until mid 10 so even if you have an 11 like myself, they may still be the old style. My build date is 4/1/10 so I have the original lead copper design.

Yea a video is needed though.

My Production date is actually 2010-03-03.

[BayE30]

sounds like cold start on an m3... before I coded mine out, the car would sound like a 70s muscle car.

im leaning towards an exhaust leak with my fingers crossed for you.

[iwantanm3]

Originally Posted by SFCM3

sounds like cold start on an m3... before I coded mine out, the car would sound like a 70s muscle car.

im leaning towards an exhaust leak with my fingers crossed for you.

Yeah it sounds like it's just the cold start, but the noise didn't exist for me for the first few months I got it. It's also painfully loud and disappears/reappears after the car is warm. If it's not a rod bearing issue beers on me.

[eatsleepboost]

Originally Posted by SFCM3

sounds like cold start on an m3... before I coded mine out, the car would sound like a 70s muscle car.

im leaning towards an exhaust leak with my fingers crossed for you.

+1 to all of this

[Bartledoo]

Sounds like exhaust leak and/or cold start cycle (which also sounds like an exhaust leak).

[Jmags41]

Originally Posted by eatsleepboost

+1 to all of this

Originally Posted by eatsleepboost

+1 to all of this

Agree with these gents on a potential exhaust leak. I've had one on a different set of engines but it sounded almost exactly like that. Are all your temps/pressure normal?

[Loki Motorsports]

I agree with the Cold start being the culprit. My car makes this SAME noise every morning when I start it. It does happen while in traffic as well, when the motor gets toasty, and it kicks the fans on. (Annoying as hell, because the free-rev of the motor gets all wacky, and makes it a PITA 6MT to drive until it goes away.) But due to the nature of these engines, this noise is a given. High compression, and nice tubular headers will do this. I have checked mine for exhaust leaks multiple times, and have yet to find one. You might learn, as I have... To take it for what it is, and enjoy the unique sound. I would immediately rule out bearings... and continue to enjoy your car!