Yes, get it up in the air on a lift when the wheels are supported and bounce it. The noise should be very apparent. Often using your hand to feel for the vibration portion of the squeak can pinpoint it.

Most likely you have a lower A-arm bearing that is rusty, typically the lower outer part by the wheel. It could also be the vertical plastic swaybar link.

Let us know what it was.

Haasman

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'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)