I am indeed a CIA agent ......just kidding. Got the car back from dealer. It is under warranty. They said there was some scratch mark on the camberarm, but they are not sure if that is the cause. Thanks for the aligment advise, but I pick up the car before seeing your post.
For the first two years of this car, it was driven in the central pennsylvania area. In winter, they put salt on road to melt the snow/ice. I do remember I ran over a concrete bumper block 2 years ago in a parking lot. It was at night and I did not realize there was one in front of my parking spot. Could that be the initial insult and caused the fatigue fracture later? Other than that, there is no other possible cause i can think of.
Thanks for all the concerns.

 

wow that is rediculous

 

Ha, Ha. Welding smack. My dad's a welder. Sounds like something he would say to me when I was growing up. Probably why I'm a CPA.

 

Thanks for the update....Glad it worked out....

Also glad to see my rust observation held water....

Weakened by rust/elements and damaged parts do break....

 

i have a 04.5 g35 suspension w/ 2k miles on it. If you need it please let me know!

 

Agree, that part looks to be very bad welded, ( factory??? )

I mention this because when a buyed last year,for my wife, a Honda Odyssey 2006 model, there was in the dealer a brand new Odyssey with a reparated sliding door, The customer notice the repair because that part didnt had the factory UPC sticker required by law. ( and it was with 2 miles in the odometer )

Did you do "Donuts" with your car or lots of "Burn-outs" or "Hard Launches"
or did you live near the beach or transit daily in very bad roads???? Your car looks very rusty in the bottom and if you look closely you will notice marks in the upper arm like it was hitted by the broken arm, like the other guy says, it looks that it was broken by constant bending, the color of the paint in the broken area and the perfect way that it breaks tells that.

 

looks like someone hates your @$$ because that $hit looks like it was sawed off

 

file a complaint with the nhtsa. That is fairly significant. It is good that they fixed it under warranty, but if this is a repeat case, it should be looked into.