[Tallgeese179]

Recently I’ve noticed that my car has a speed-dependent noise coming from the front end, but I have not been able to track it down. Thinking back, I’m recall hitting a relatively large pothole a while back with my front right tire, though I don’t recall the noise starting right after that incident.

I have noticed the following symptoms:
-Light rhythmic thudding coming from the front of the car around 20-30 mph (no wheel shake)
-Noise is present when coasting in neutral (6MT) and when in drive
-Around 60-70 mph the thudding becomes more noticeable and the car feels very unstable, along with mild wheel shake

My first thought was that it could be a wheel bearing issue, even though the typical whirling noise wasn’t present. I checked for failure the following ways:
-Lifting the car up and checking for play (hands at 12 and 6, push/pull on wheel). No play
-Removing wheel, caliper, and discs to freely rotate hub. No excessive noise present
-Testing wheel hub for run-out using dial indicator. Less than 0.004” runout on left/right hubs

Next I thought it might be the wheels were out of balance. Conveniently, winter is in full effect so I put the winter set on. The noise has reduced drastically due to the snow tires being much softer than my Eagle F1s. However, when I went on the highway two days ago I noticed the same rhythmic thudding and instability as before (around 60-70 mph).

Anyone have a similar experience or have recommendations on where to start?

Car Info:
2009 335xi, 6MT, ~75K miles

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SOLVED (6-20-16)

I installed coilovers over the weekend. I scheduled an appointment at my dealership for an alignment and Road Force Balance (in hopes of getting rid of the thudding). On the way there I jumped on the highway to see if I could replicate the problem (sever thudding when decelerating from 90+). Got up to ~100 and coasted...no thudding!

The steering was all over the place since the alignment was messed up from coilover install, but there was no vibration at high speed. Needless to say, I skipped on the Road Force balance.

MY CONCLUSIONS:
I'm convinced based on the rust/leaking visible on all of my struts, they had pretty much failed, allowing the some resonant frequency at ~90 to go wild without much damping.

[335xs2dinan]

possibly a shot thrust arm bushing

[Tallgeese179]

Originally Posted by 335xs2dinan

possibly a shot thrust arm bushing

Are you specifically referring to the failure prone fluid filled upper control arm bushing?

I remember looking over them last spring thinking that they may have failed due to the wheel shake that I was experiencing during braking. It turned out it was bad rotors along with improperly balanced tires.

I'll make sure to look over them in the next week, though I have my doubts about them failing. The reason is that (from what I have read on other forums), the vibration would be translated to the steering wheel if the cause was something like a failed bushing, especially during hard braking. So far the steering wheel is very stable while the noise is audible.

I have noticed another very specific noise that only occurs if the car is cold and hasn't been driven (commute to/from work). It sounds almost like a strong wind blowing, coming form the front end. As I pick up speed the sound increases in volume and begins to fluctuate somewhat randomly. The sound is best described as sounding like Morse code. This leads me to think again that maybe the front right wheel bearing is slowly losing lubrication/failing, but I can't detect if the wheel is locking up because the car is AWD.

Anyone know if the wheel bearing can fail while continuing to pass the testing that I mentioned in the initial post (push/pull on wheel with hands at 6/12)?

[frenchi]

Originally Posted by Tallgeese179

Are you specifically referring to the failure prone fluid filled upper control arm bushing?

I remember looking over them last spring thinking that they may have failed due to the wheel shake that I was experiencing during braking. It turned out it was bad rotors along with improperly balanced tires.

I'll make sure to look over them in the next week, though I have my doubts about them failing. The reason is that (from what I have read on other forums), the vibration would be translated to the steering wheel if the cause was something like a failed bushing, especially during hard braking. So far the steering wheel is very stable while the noise is audible.

I have noticed another very specific noise that only occurs if the car is cold and hasn't been driven (commute to/from work). It sounds almost like a strong wind blowing, coming form the front end. As I pick up speed the sound increases in volume and begins to fluctuate somewhat randomly. The sound is best described as sounding like Morse code. This leads me to think again that maybe the front right wheel bearing is slowly losing lubrication/failing, but I can't detect if the wheel is locking up because the car is AWD.

Anyone know if the wheel bearing can fail while continuing to pass the testing that I mentioned in the initial post (push/pull on wheel with hands at 6/12)?

I got exactly the same symptoms as yours on XI car and already replaced control+thrust arms,next week i will replace struts with Bilstein B6 but almost sure now that it comes from the wheel bearings...same strange blowing sound only on high speed over 100km and absolutely silent on low spped. What is your mileage ? I am on 85x miles.

[Tallgeese179]

Originally Posted by frenchi

I got exactly the same symptoms as yours on XI car and already replaced control+thrust arms,next week i will replace struts with Bilstein B6 but almost sure now that it comes from the wheel bearings...same strange blowing sound only on high speed over 100km and absolutely silent on low spped. What is your mileage ? I am on 85x miles.

Currently my car is at around 75K miles. It appears that you have a similar problem, but inverse of mine. I only hear the wind blowing sound when the car is really cold and at low speed. The sound gets quieter as the car warms up.

However, today I was testing out some more scenarios on the drive to work. It appears that the wind blowing noise only occurs when the car is in gear. Specifically, the noise drops off when I slip the shifter out of gear and starts back up as soon as the gear engages (clutch still depressed).

From this, I conclude that the wheel bearing isn't the source of the wind blowing/whining noise and is instead likely something with the transmission.

**EDIT**
I took the car out on the highway yesterday to test out the 60-70mph stability. Right around 62mph, the right tire begins to make a loud rhythmic noise. Unlike I stated before, there is steering wheel shake present.

Maybe the first poster was right about the control arm bushing (failure prone fluid filled one). I'll look over all of the linkages this weekend and report back. Regardless, I will also look into buying a set of Strongflex yellow bushings, if nothing else to improve the steering feel/stability.

[frenchi]

Originally Posted by Tallgeese179

Currently my car is at around 75K miles. It appears that you have a similar problem, but inverse of mine. I only hear the wind blowing sound when the car is really cold and at low speed. The sound gets quieter as the car warms up.

However, today I was testing out some more scenarios on the drive to work. It appears that the wind blowing noise only occurs when the car is in gear. Specifically, the noise drops off when I slip the shifter out of gear and starts back up as soon as the gear engages (clutch still depressed).

From this, I conclude that the wheel bearing isn't the source of the wind blowing/whining noise and is instead likely something with the transmission.

**EDIT**
I took the car out on the highway yesterday to test out the 60-70mph stability. Right around 62mph, the right tire begins to make a loud rhythmic noise. Unlike I stated before, there is steering wheel shake present.

Maybe the first poster was right about the control arm bushing (failure prone fluid filled one). I'll look over all of the linkages this weekend and report back. Regardless, I will also look into buying a set of Strongflex yellow bushings, if nothing else to improve the steering feel/stability.

I am sure that thrust arms bushings will arrange your steering shake,but will not fix the blowing sound as happened on my car....we are looking on a mix of problems probably i will keep you informed once i find out what's wrong with the drivetrain

[Tallgeese179]

I wanted to give a quick update on the process of tracking this problem down.

Since my car has x-drive, the usual upgrade to the ///M control arms wasn't an option. I ordered the StrongFlex yellow polyurethane bushings and installed them at home using a shop press from Harbor Freight.

Some things I learned:

• The recommended "look for fluid stains on the bushing/control arm" approach didn't work in my case. There were no signs that the bushings had failed, when viewed from underneath the car. After removing the control arm I quickly realized they had failed spectacularly. Both sides had 1/2" long cracks in the rubber and were bone dry. Looks like they've been like this for a while.

• Installing the poly bushings is a bit of a pain in the a**. Trying to insert them lined up with the hole (concentric) resulted in the lips of both bushings starting to form fissures from pressing on the edges on the control arm hole. The trick was to skew them a little (like you would with a smaller rubber grommet) and get the lip started. This technique worked well and didn't cause more fissures.

• Installed using the grease provided, the bushings do not squeak/pop. I have put around 5K miles on them so far with no issues.

From my experience, I highly recommend this upgrade to anyone looking for a tighter steering feel. The turn-in response has improved significantly, with only a minor increase in NVH.

Sadly, however, this has not cured the problem completely. I noticed recently on the highway that although the vibration is gone at speeds up to ~80, pushing past 80 and especially around 110, there is still significant vibration and wobble. It still feels like it's coming from the right front.

[Tallgeese179]

Also, since I had updated the control arm bushings and added 20mm spacers (aftermarket wheels had wrong offset), I decided to get an alignment done at the dealership.

The result was that the technician was not able to get the front right and rear right camber within spec. The SA told me that the front was probably due to a bend strut and the rear was due to a bent knuckle.

The front I can understand, since the car has nearly 80K and has spent it's life between NJ, OH, and now in PA. I'm looking to replace the struts/shocks with Bilstein B4s in the near future, along with some of the related components.

I am, however, wondering if this is really what's causing my problem at high speed. I also do not understand what the SA meant by "rear knuckle". Any insight into the problem would be greatly appreciated.

Attached is the alignment print-out that the SA gave me.

[jwebb335xi]

Originally Posted by Tallgeese179

Currently my car is at around 75K miles. It appears that you have a similar problem, but inverse of mine. I only hear the wind blowing sound when the car is really cold and at low speed. The sound gets quieter as the car warms up.

However, today I was testing out some more scenarios on the drive to work. It appears that the wind blowing noise only occurs when the car is in gear. Specifically, the noise drops off when I slip the shifter out of gear and starts back up as soon as the gear engages (clutch still depressed).

From this, I conclude that the wheel bearing isn't the source of the wind blowing/whining noise and is instead likely something with the transmission.

**EDIT**
I took the car out on the highway yesterday to test out the 60-70mph stability. Right around 62mph, the right tire begins to make a loud rhythmic noise. Unlike I stated before, there is steering wheel shake present.

Maybe the first poster was right about the control arm bushing (failure prone fluid filled one). I'll look over all of the linkages this weekend and report back. Regardless, I will also look into buying a set of Strongflex yellow bushings, if nothing else to improve the steering feel/stability.

Check wheel, tire, tie rod and other control arm as well..

[PrematureApex]

Doubt your strut is physically bent, but it is possible.

The knuckle is the upright. The hunk of iron the wheel bearing and hub are pressed into and that the control arms attach to.

Up front, the knuckle includes the opening/clevis that holds the bottom of the strut.

TS polys will amplify any out of balance wheels, etc. Some added vibration at high speeds wouldn't be abnormal if something else was out of balance.

[ajsalida]

Hope you get this sorted soon.

In addition to everything else you're looking at, the axles and their CV joints can go bad and make noises/vibrations like you're describing. Esp if you took a big hit. Sometimes the boots crack and lube leaks out and the bearings get dry, or they can get directly damaged from big pothole hits.

If you can get under there and look very carefully at the inner and outer boots, all the way around and between the bellows, and rotate the wheel while listening for grinding or binding.

Also, and I hate to bring this up, there could be issues with the front diff, Check fluid level and for metal shavings in there.

[jwebb335xi]

Originally Posted by Tallgeese179

Also, since I had updated the control arm bushings and added 20mm spacers (aftermarket wheels had wrong offset), I decided to get an alignment done at the dealership.

The result was that the technician was not able to get the front right and rear right camber within spec. The SA told me that the front was probably due to a bend strut and the rear was due to a bent knuckle.

The front I can understand, since the car has nearly 80K and has spent it's life between NJ, OH, and now in PA. I'm looking to replace the struts/shocks with Bilstein B4s in the near future, along with some of the related components.

I am, however, wondering if this is really what's causing my problem at high speed. I also do not understand what the SA meant by "rear knuckle". Any insight into the problem would be greatly appreciated.



Attached is the alignment print-out that the SA gave me.

Did you ever resolved your problems?

[Tallgeese179]

Originally Posted by jwebb335xi

Did you ever resolved your problems?

I actually had an appointment yesterday after work at my dealership. The tech went out for a ride with me, but because we were limited on time and couldn't get out on to the highway, we couldn't replicate the problem.

Surprisingly, he just complimented me on the car's ride/power and said that I should either:

-reschedule the inspection for mid-day when we can get out onto the highway
-drive it, see if things get worse, then report back

He said the out of spec camber was nothing to worry about. I will likely be getting new coilovers soon (unrelated), so I'll look around more closely during that install and report back in case I figure anything out.