I noticed that my 530i (2006) made a really loud banging or thud noise when going over a bump going down an off-ramp at about 40-50mph. Then this week a similar thing happened going over some railroad tracks. The noise was loud enough to startle me, it sounded pretty violent, enough to fear damage. The car drives fine from what I can tell, and there is no vibration or irregularity in the steering.

I have the sports package and everything is stock (I have 52k miles CPO warranty), except the tires which are Michelin PS2 18 inch. I recently increased the tire pressure to 36.5psi (from 32) in Front and 38.5psi (from 35) in Back. The increased tire pressure improved handling considerably.

Could the loud noise be the infamous control arm issue or bushings?

 

where was this noise coming from? i'm assuming the fronts? if so then its possible the upper shock mounts may have failed. this would be the first place i'd check. good luck

 

I remember it happened as my front wheels were going over the bump in the road or railroad tracks, so I'm assuming the noise is coming from the front of the car (front wheels/suspension).

 

What the symptoms of a failed upper shock mount? Does the car handle differently or have a stiffer ride?

 

symptoms would be noises you described. your shock movement (up and down extension) is the same rate as the vehicles up and down movement. if your shocks aren't properly secured up top on the shock mount (say a failed upper mount bearing) your vehicle will "bang" onto this mount when it tries to move up and down. your shocks rate of travel is now slower than vehicle. now this is just one of any possible scenario. but i'd check here first.

control arm bushing will result in uneven tire wear, worn tread on either side of tire, inbound or outbound. good luck

 

Hi. A big thing to check is that you haven't broken a front road spring. I did it going gently round a bend, and I seriously thought I'd gone over a rock in the road.....far worse than a ball joint "clunk". Turn the steering wheel from lock to lock while stationary and see if you get a loud clunk. Good luck!

 

Was it a bang or is it like a knocking noise. Could also be sway bar links. They are notorious for going bad and causing noises over bumps