Front end groaning when driving, at my wits end - need you input please

[whiteghost1]

My e39 is make a groaning sound from the front end which driving me nuts. The groan happens during almost any type of road imperfection, and sounds exactly like when a BMW clutch LSD doesn't have enough friction modifier and groans around turns. I can also 'feel' the groan slightly in the steering wheel and in the dead pedal when driving, if that gives any clues.

I've inspected the entire front end...... poked/worked/pryed every component and everything checks out as secure and in good shape visually. I've swapped out the complete front strut assemblies with zero change in the groan.
Here are my observations, groans under the following:

- doesn't matter if it's small road imperfections to large potholes, speed bumps, driveways, etc....
- front end loading doesn't effect it - meaning it happens during accel, coasting, braking and so on.
- turning doesn't effect the groan - low speed, high speed, sharp turns, long sweeping turns, etc....
- ambient temp and humidity levels irrelevent

Basically there is no rhyme or reason to the source & I'm at a loss where to look or what to do/check. I don't want to just throw parts at it with the hope that something solves it.

Anyone have any ideas or similar experience?

Any help would be greatly appreciated.

[MIKYZZ4]

Have you thought of inspecting your motor mounts?
BTW, do you have cross braces installed?

[whiteghost1]

Have you thought of inspecting your motor mounts?

That did cross my mind but it's one of the things I haven't checked, I'll be sure to inspect that tomorrow morning.

[BimmrMeUpSnotty]

Strut bearings.

[auaq]

Wheel bearings? Any play in the wheel when you wiggle it side to side and from top to bottom?

[bluptgm3]

Stepping out on a limb here…how old is you power steering pump reservoir and fluid? The reservoir contains a filter and needs to be replaced periodically.


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[StephenVA]

The first step is determining when the noise occurs. it cannot be totally random.
Only occurs when turning the wheel left or right? Only happens when rolling? Nothing occurs when stopped? In gear and or in park? Engine coasting, under acceleration? Engine off?

if you can make it do it when stopped, see as mention strut bushings, steering linkage, PS system. Look at the mounting bolts etc.
under braking, make sure all the mounting bolts are tight and torqued to spec.
the real question I have is at the mileage your at what has been replaced recently?
The list of "what it could be" is as long as the parts on your car. There is a very standard list of what should be replaced at a given mileage point as all the parts have given their service life one mile at a time until they are all worn out.
Which year and engine size are you working on?

[JimLev]

Stepping out on a limb here…how old is you power steering pump reservoir and fluid? The reservoir contains a filter and needs to be replaced periodically.

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The filter (plastic screen) is not replaceable unless you replace the resevoir itself. However you can unscrew it (won't come out of the resevoir) and flush it out with your favorite solvent, then screw it back in.

[MIKYZZ4]

Stepping out on a limb here…how old is you power steering pump reservoir and fluid? The reservoir contains a filter and needs to be replaced periodically.


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If the groaning sound ONLY occurs while turning the steering wheel during a turn,
then your steering pump and fluid level or fluid condition are the primary suspects.

[rdl]

Never had these symptoms, but some thoughts in addition to those above.

I'd first try to localize to a side or corner. Set a piece of plywood or a length of 2x4 on smooth street & drive over it with each wheel separately. Does the groan occur on one side only or both? Groan on front hitting the obstruction only, or over a rear tire too?
Any difference driving forward vs backward over the irregularities?

Can you reproduce the groan by leaning on the fender to jounce the corner up & down? Again, one or both sides?
Possible to create the groan while jacking the car? Or when letting the jack down?
Turning the steering wheel while stationary?
If yes to jouncing, jacking or turning it might be possible to very carefully (as in safely careful) listen or feel for the source with help from an assistant - one to create the sound, other to search for location.

Also, it would help to know if you have an L6 (rack & pinion) or V8 (steering box and drag link).
Any speed dependence, e.g. no groan below 10 mph? Or none above 50?