Engine problems of the 1999 Chevrolet Monte Carlo

Sheared bolt was found on my garage floor after driving to and from work. Tow truck driver said he had never seen this happen before. Dealer claims I hit something, but no other damage is visible. I didn't drive because I felt it was unsafe, but would appreciate knowing if the is a manufacturer defect to obtain cost of repair and towing and hopefully save someone else's life.

:this seems to be a ongoing problem with a large margarity of Monte Carlos. My understanding is that a dealer memo went out in 1998 notifiying chevy dealers of possible piston problems. I have spoken to a few Monte Carlo owners and find this to not be a rare problem. Pistons are blowing through the engines while driving. I was aware enought to hear a knock and knew enough about cars to get it checked I spoke to a girl who owns a 1999 Monte Carlo her engine blew while driving down the road at 17,000 mile. She now has a new engine with 7,000 miles and it has a knock in the engine. This is a very serious problem I am concerned for the saftey of my children and myself as well as other Monte Carlo owners who are not aware of this problem and might consider taking there familys on a long trip somewhere. Possible leaving them stranded or hurt if the engine blows while driving on the highway. Chevy is aware of this problem yet it still continues to manufacture the same engine from the original memo date of 1998 to present. This shows a serious lack of saftey or concern for consumers on the part of chevy. Please help me as this is a large expense and I truly do now have a concern for my familys saftey on future planned trips. I bought a new car for the security of knowing my children will be safe , for this reason I did not buy a car that was old or with a rebuilt engine. Yet chevy solution is to rebuild my engine "end of story " according to them . You are probably the only chance ending the productin of this faulty engine. Please contact me as soon as possible. Thank you.