I have a 2004 jeep liberty that had over 170,000 miles on it. My first car, got back in May. Noticed heat does not work. It went in to dealer this mornong, to find out the problem ( my father brough it in). Problem came back.. it was the heater core. Well, after work, I get in the jeep and start it... it was very rubbly, more so than usual and I thought it was just cold. I started driving... thats when a cloud of white smoke filled my back window, the engine light came on, and it smelled like rotte eggs. Had to have my father pick me up... who was absolutley furious! The jeep was running GREAT before going into the dealership... I am bringin it back in tomorrow morning... but I was juat wondering what the hell did the mechanics do, or not do?!