[gomichaelkgo]

Originally Posted by colmeir2

Are you guys talking about that harmonic buzzing happening? I just got my 14 cpo 335i and I heard that kind of harmonic buzzing while in sport mode the other day. Definitely worried now!

Look for a weight (about the size of a cat food can) clamped to an AC hose going into the dash board. If your '14 doesn't have the weight, get the TSB done to add it. Resonant vibration in the hose can shake the evaporator inside the dash.

[gomichaelkgo]

Originally Posted by gomichaelkgo

HenryX, it occurred to me that the AC compressor could be pulling the crankshaft to one side due to the extra force on the serpentine belt. Turning on the AC might not allow the crankshaft bearing to make its wobbly sound.

There's a TSB to add a harmonic damper (fancy word for a weight) to the low pressure AC hose. It can resonate under certain loads and shake the evaporator inside the dash.

[imperialbluecupertino]

This is the AC low pressure line resonance noise. It's described as "N55 engine rattle" "F30 engine noise at 2500 rpm" "N55 vibration sound under load." It sounds like something is really really wrong with the engine and makes you instinctively back off the throttle every time you hear it. Really kills enjoyment of the car.

I got my 2012 F30 used and the noise was just awful. After a bunch of searching I finally found this thread and a few others linking to the solution. I literally went to the parts department, paid them $17, went to the parking lot, attached the weight, and NO MORE NOISE. EVER!

For completeness, the part number and SIB are:

Additional weight 64-53-9-322-952


SIB 64 01 14


I asked my Service Advisor and they had no idea. I think this issue ends up making a lot of early F30 N55 owners unhappy. I think it's part of why I got a good deal!


Thanks forum people for helping me fix this!

[joeyxbender]

I'm so glad I came across these videos. Been experiencing the same issue intermittently as well.

My 2013 f30 335i (pneumatic waste-gate) has started making a "metallic rattling" or "metallic vibrating" noise when accelerating lightly from a stop. This metallic vibration noise sounds VERY similar to some of the videos posted on this thread.

I've attached a video below where you can CLEARLY hear the metallic vibration between 2k-3k rpm's when lightly accelerating from a stop:

https://youtube.com/shorts/MeKYDv978a8?feature=share

PLEASE ADVISE!!!! And let me know if there is any problem accessing the video…

[Dirty35i]

So is it the ac line missing the weight or the waste gate 😑😑 somebody help me out…. Sorrry to bring this topic back up buuut im stuckk … i dont want to take it to a shop if its a simple fix 🥲

[Randy Johnson]

I think it sounds like the parking brake cable clip.