I bought a lexus es 300 in september 2014, I got an oil change mid November. I requested conventional oil because I was told that is what the car was suppose to use and that was cool with me because it was the cheapest. I was told by the man at the oil change place that I could NOT use conventional at ALL and that I had to use synthetic. I was unsure about this but I went ahead with it because I knew that they look this information up in their computers. I paid an extra 30 dollars for the synthetic oil. approximately 1400 miles later and not even 3 months later my car broke down and the engine has failed. The dealership is saying that it was the oil change place fault and the oil change place is saying that the issue had to be there before they changed the oil and it is the dealership fault. When I broke down no oil was showing on the stick, when the car got to the dealership they said that there was no oil and caused the engine to lock up. I told them I just received an oil change and that they used synthetic oil, the dealership told me that was the problem because the synthetic oil burns faster in this model car. Right now they are going back and forth about who is to blame. I have been reading trying to figure out what could have happened. The car has been checked for oil leaks and there are none. Can someone give me insight on this. What could have happened to the oil? Could the synthetic oil have caused this problem? Could there have been something wrong with the engine to cause it to burn 5 quarts of oil in 1400 miles?