Unexplained front-end knocking

[jimmy47785]

2003 BMW 330d Sport Touring, 6-speed manual gearbox, about 149,000 kilometres.

I have been pursuing a persistent knocking noise in the front end for over a year and have explored numerous sites for solutions and recommendations.


I changed the entire front suspension, including the bushes and both inner and outer ends of the rack, approximately 10,000 miles (3 years) ago. Recently inspected, and they remain structurally sound.
Recently replaced the lower control (lollipop) bushings.
I have recently replaced the rack with a refurbished one.
Recently substituted the shocks and top mounts with Sachs, as I intend to sell the vehicle, although this alteration appeared to have no effect.
The steering column link was removed and appears to be in excellent condition.

Today, I detached the drop links and circumnavigated the block; the knocking persisted. I am aware that it is not associated with the anti-roll bar in any kind. I also navigated it over several curbs cautiously, and it appears to be more problematic on the front left.

All components were torqued upon installation and subsequently re-verified.

The only components on the front that I have not changed are the engine mounts; however, the issue does not appear to be related to them.

Do you have any recommendations? (apart from incineration, I am inclined).

I sincerely hope it is a little issue and not related to the front subframe mounting points. I intend to sell the item, but it is resisting my efforts. It seems to possess an awareness of my intention to sell it.

[developer]

Have you examined the wheel bearings?

[Mistral]

Once all components have been replaced, including bushings and strut top mounts, my subsequent recommendation for an E46 would be to verify the absence of mushrooming on either strut tower, as this could elucidate the pronounced knocking on one side.

[jimmy47785]

I will examine it today and provide updates with photographs.

[jimmy47785]

Affirmative. Inspected them yesterday. One was recently substituted.

[jimmy47785]

I examined my strut tops and do not believe they are distinctly mushroomed. Perhaps marginally. I placed a ruler on them, and there is a tiny curvature; I am not if this is typical.

[jimmy47785]

[jimmy47785]

[Mistral]

They appear satisfactory, my friend. BMW has issued a preventative solution for mushrooming. If you are maintaining the E46 aesthetic, consider that they are inexpensive and consist of a pair of plates positioned between the turret tips and the bolts (similar to a strut brace, but lacking the central brace that connects the two).

[jimmy47785]

Indeed, I installed these when I replaced the entire suspension a few years prior.

I sincerely hope this knocking is due to a little issue, but it increasingly appears to be related to the subframe mounting points. This vehicle does not justify the expense of the repairs.