Metallic clacking sound when going over bumps at 30mph+

[will731]

Hey guys, I've had my 2005 imola zhp for about 3 weeks now and have noticed that over bumps I get a metallic clacking sound from the front suspension. The noise happens when hitting small sharp bumps, if that makes sense. It sounds like its coming from the driver side but that may be because I'm obviously on the driver side. I have changed the fcab and sway bar links because I had found them worn out. Needle to say they didn't fix the noise. The sway bar itself feels tight in its mounts, the ca have been changed by PO and the ball joints on them look to be in good shape. They also felt tight when I inspected them when doing the fcab. I'm starting to wonder if this is a normal E46 noise. Any advice would be appreciated. Thanks

[ELCID86]

Not normal. I would have guessed CAB, I'm sure others here will have more ideas.


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[LivesNearCostco]

Not normal but I can't think of a likely cause beyond what you've done. Could be failing strut mount rubber or the bearing inside the strut mount. Could be failed driver's side motor mount, but then you should also get a thunk when you let the clutch out in 1st or 2nd gear, as the engine rises up and settles back onto the failed mount. Perhaps loose reinforcement plate (or one of the 8 bolts) but I assume you removed and replaced that plate when replacing your FCABs.

[will731]

I do have a thud when releasing the clutch in 1st and 2nd, actually all gears. The thud will lessen in harshness as I shift up. I have confrimed that my rear diff mount(the rear most one) is cracked significantly so I assumed it was just the diff clunking. The front struts and mounts and bearings were just replaced by PO and he installed the e46 strut tower reinforcement plate as well as an m3 strut bar. It does sound alot like he may of left something loose. Any usual suspects that people usually leave loose or that back out? Thanks alot for the replies!
Not normal but I can't think of a likely cause beyond what you've done. Could be failing strut mount rubber or the bearing inside the strut mount. Could be failed driver's side motor mount, but then you should also get a thunk when you let the clutch out in 1st or 2nd gear, as the engine rises up and settles back onto the failed mount. Perhaps loose reinforcement plate (or one of the 8 bolts) but I assume you removed and replaced that plate when replacing your FCABs.

[danewilson77]

How about FSM's? Blown shock?

[LivesNearCostco]

When letting out clutch in low gears, cluck from the rear usually diff bushing. Clunk from the front is FCAB (but you replaced yours, and it's better known for clunking under brakine) or motor mount. You can visually inspect the driver's side motor mount from below using a mirror or from above by removing the airbox and looking down with a flashlight. If it's really gone, you'll see oil on top. Could also reach up and feel the top of the mount with a paper towel if the car is on jackstands or a lift.

Maybe if both motor mounts are broken, the heat shielding on top of the right-side mount could rattle, but normally just the driver's side mount breaks.

[will731]

Front shocks are new. Front sway bar mounts looked ok and were tight-ish. The sway bar links are new and the sway bar it self is completely encapsulated with rubber. I don't think it would be able to make clacking metallic noise.

[danewilson77]

Front shocks are new. Front sway bar mounts looked ok and were tight-ish. The sway bar links are new and the sway bar it self is completely encapsulated with rubber. I don't think it would be able to make clacking metallic noise.

Sway bar? What about front shock mounts? When were those last replaced?

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[will731]

Oh FSM lol okay. They were replaced maybe 6 months before I bought the car.

[will731]

I need to get it on my lift again and see if I can duplicate the noise in the air.

[Indvdl M]

Might it be the brakes? I have a rattling metallic noise over sharp bumps but if I put light pressure on the brake pedal it's dead silent. I will be inspecting the issue this weekend. Good luck

[will731]

Noted! I will check the brakes as well. Thanks!

[kpro]

BMW has a bulletin for this, does it happen at low speeds, especially when going over bumps or turning?

[Smilez]

SOUNDS to me your control arms are going out. Lift the car up and see if the wheels have any play. They shouldn't wiggle.

[will731]

BMW has a bulletin for this, does it happen at low speeds, especially when going over bumps or turning?

What does the TSB say?

[will731]

SOUNDS to me your control arms are going out. Lift the car up and see if the wheels have any play. They shouldn't wiggle.

I do have side to side wiggle. And while sitting in N at idle I can feel some play in the steering wheel. Steering guibo is brand new. Steering rack worn?

[Smilez]

I do have side to side wiggle. And while sitting in N at idle I can feel some play in the steering wheel. Steering guibo is brand new. Steering rack worn?
Your ball joints are probably warn out on your control arms. Possibly ebbed your control arm bushings. Have it verified at a Firestone. If indeed they are out, but some meyle hd replacement.

[will731]

I'm an Audi tech so I do all the work myself. I just replaced the control arm bushings with bmw parts. The Meyle hd's were worn out. Didnt remove the entire ca though, PO said they were replaced. I did find that one side is meyle the other seems like its genuine so Maybe the genuine one is the original. I may just bite the bullet and get both control arms.

[will731]

After the ca bushing replacement the noise during parking lot manuevers was somewhat cured and the slight steering wheel vibration at 80 is gone. So I am making progress to my goal of a healthy suspension. Rear diff bushings next. I also have to verify that my engine mounts are ok. Lots of clunks during clutch disengagement and engagement.

[jakksfor20]

Just dealt with similar issue after putting PSS coilovers on my 323ci. Metallic clacking on very small bumps at low speeds worth the worst. Could really hear over the expansion joints in my concrete drive way. I troubleshot it by bouncing each side of the front suspension with it on the ground. It made the noise on the driver's side when I bounced the passenger side which kind of clued me in that it was sway bar related. Ended up being the bottom sway bar end link bolt was just slightly loose. I got no more than a single turn on it. I hadn't even touched that bolt during the coilover install. Tried the bouncing again, no longer there. Then took it for a spirited drive and came back to same expansion joints and no more problems.

[will731]

Might it be the brakes? I have a rattling metallic noise over sharp bumps but if I put light pressure on the brake pedal it's dead silent. I will be inspecting the issue this weekend. Good luck

Haha confirmed today, noise is completely gone with light brake pedal pressure! Also rove my buddies 330i and it has the same noise. I bet its the vibration dampener spring on the caliper. Maybe it need some lube. Will check this out asap. Thanks to all that replied!

[llll1l1ll]

I just wanted to chime in and say I had the same issue. I put new pads on old rotors and I had this horrible clickity-clank rattle sound over bumps. I thought it was the end links rattling. Turns out, it was my pads slapping the rotor. I put new rotors on and the sound is gone.