E500 squeaky suspension
 

Recently purchased a used 2003 E500 roughly 50K miles, about 3 months later started hearing a squeak coming from the drivers side when entering/exiting the car, also when driving over bumps in the road. Only noticeable driving when windows are down and radio off but very noticeable nonetheless. Also hear it when driving at slower speeds over bumps and such. Any thoughts? It's actually at the service now and they are mentioning ball joints, just wondering if it could be anything else just in case. Thank you.

I tried a cheap trick once to isolate a problem... I sprayed wd-40 on each piece of rubber until the squeaking stopped.. ( it was a q45).

When I found the culprit, I replaced it. The wd-40 is actually bad for the rubber ...but in an isolated instance it helps trouble shoot a problem.

Have a good look at the front swaybar bushings.
Other than that, you could have somebody " bounce " the car up and down, while you try to isolate the source of the squeak. ;)