I was driving down the highway and as I was going up a hill my car made a loud noise and then shut down. I had to coast to the side of the highway. I was stranded on the side of the highway with my two year old for 3 hours while I waited for a tow truck. I had to have my car towed and it was confirmed that my engine had locked up. My car has 106,000K miles on it and has had all routine maintenance completed on it. There were no warning lights before this happened and the mechanics do not know why the engine locked up.