I have a '11 Elantra Touring with 12,000 mi. Its been having a problem especially when driving on city streets. Sometimes when I go over bumps or turn into (or out of) raised parking lot areas, there is a metallic sounding clunk from under my car. It almost sounds like if you put a dent in an oil drum and let it pop out.

 

Check the sway bar end links. Actually, if it's a 2011, take it back to the dealer to have it checked and fixed under warranty.

 

We had this issue with ours. NovaResource is almost certainly right. It was fixed under warranty (hey, if it's a 2009 you should probably get it fixed under warranty and sound disappeared.

Seemed to firm up handling, too.

 

When I had my 09 ET, exact same thing...sway bar end links. Really noisy... it sounded to me like some tool was rattling/rolling around in that rear compartment.

 

Thanks for the suggestions. I'm still working on getting it to the dealer, but I'll let you guys know!