So i need some insight I have a 07 335i that recently developed a thumping...

So i need some insight. I have a 07 335i that recently developed a thumping/tapping noise from the motor that correlates with the rpms. The noise is loudest between 2-4k rpm with a steady increase. If i throttle to much it isn't there. What the hell could it be? I don't know how to completely describe the sound and every time I try to record it my loud ass exhaust keeps the camera from hearing the thumping. It kinda sounds like if you have a flat and it thumps, but it comes from the motor for sure and its a quick thumping that increases speed with rpm increase (doesn't have to be under load or in in gear). If that makes any sense.. I have no idea what it can be, and want some ideas to see if i can get help diagnosing and possibly diy to save money on mechanics.

Thanks ahead of time!

%d comments
  • Well i'm bored at work and thought maybe someone could have some insight. In the end I usually visit my indy anyways.

  • Cars
  • Yeah when it comes to issues that are dependent on hearing noises its really difficult over fb

  • Yea i know. It was a longshot. It sounds like a knock, upon listening to some videos on youtube/forums/etc it does sound like the start of a spun rod bearing but who knows.

  • See what i mean. Its like googling a pain in your side.... everything says you have cancer.

  • Lol

  • exactly. I'm hoping its nothing major.

  • Its probably a loose* exhaust bracket or something retarded

  • Motors are really hard to kill

  • Yea true but it does happen, especially with my rotten luck. It sounds like the pistons are hitting high density foam as odd as that seems. It doesn't sound anything like a rattle. It's just strange it only happens when I accelerate slowly between 2-4k rpm and the speed of the "thumping" quickens with the increasing rpms. At first I thought it was drivetrain or clutch (because my clutch is starting to go out) but it still happens when in neutral and not moving and I just rev. I'm baffled.

  • Cars
  • I've had this happen in one of my old cars (can't remember which one it was) and I just sold it asap and made it someone else's problem (dick move on my part, i know)