[CraigFL]

Most states recognize uses car sales as "as-is" type. This means that you buy the car just as it is and it is your responsibility to check out/have the car checked out. During the presale it generally allowed to have the seller do some "puffing" which is a legal term used to describe the seller talking about his car in order to sell it. This means that terms like "it's a cream puff", "top mechanical condition", an other things are perfectly acceptable. What is generally NOT acceptable is implied/specific warranties that may not be true like -- "this car will get you around town for the next year with no problems" or "the engine was just rebuilt last month"--(and it wasn't).
Your claim, probably in small claims court, would be very dependant on exactly what the seller said -- it will be your word against his. Your problem will be if you did not have your mechanic check it out before you bought it and why you didn't do this. If the problem is serious and would have been discovered during a pre-purchase inspection, the problem may be yours.