I thought it was a sway bar link, because I could hear this clunk primarily when one wheel hit a bump but the other didn't, or while driving over uneven surfaces. The dealer replaced all four sway bar end links (mechanic's choice, not my decision, under warranty), and the clunk is still there.

It's considerable enough that I actually pulled over and checked to make sure my lug nuts were tight, it sounded like the wheel was about to fall off.

After getting it back from the dealer, it doesn't sound any better at all, so it must be something totally different.

I can even hear it if I swerve back and forth at 30 mph on a smooth road, I think when the weight lifts off the left side, and when it settles back down.

The next time I bring it to the dealer will be the third time for the same problem. If I can determine that this significantly effects the safety or value of the vehicle, I will persue my rights under the Florida lemon law.

Any help is appreciated.

 

Responding to an old thread here but this is exactly the problem I'm having. I have a 2008.5 Mazda 3, about 2 weeks off the boat and under 500 Klm's. I haven't returned to the dealer yet, thought I'd check online while waiting to get a chance to bring it in.
I also pulled over to check that the lug nuts were tight. And, just as Baldy mentions, I also swerved back and forth, a little slower at about 30 klms and I could here a slight clunk. Over a relatively rough road the front end rattles and the car just doesn't feel tight. The 6 year old Kia I traded in drove tighter.
It was a warm day as well, 28C so wouldn't be the bushing problem I've read others having. Anyone else with this problem?

 

could be the splash guard hitting the bottom. i sometimes get a flapping and banging when i hit some bumps they come and go unless its birds getting stuck under my motor!

 

Might be a loose strut or another suspension part

 

They eventually found the problem on mine.

Now, I've had other cars, and worked on them myself (autocross and all that), so I know a suspension noise when I hear it.

HOWEVER, the problem turned out to be that the windshield wiper cowl wasn't torqued down properly, or came un-torqued. Apparently one of the mechanics read about it somewhere, not even a TSB, (said it would sound like front suspension noise) and they torqued it down. Haven't had the noise since.

 

engine mounts have been a problem on some 3's as well. I know mine thuds a bit, its not harsh like a ball joint or strut mount, but soft/muffled so i'm assuming an engine mount, i'm not worried since its been there since day 1.