回複：Please help! Just sold my old car...

I think fraud means you did not give him fully information about the car, that is, you knew about the oil leakage and you did not tell him. In your case, as long as you told him everything you knew about the car, there was no fraud. If there was a problem and you did not know, he bought the problem with the car and that's his problem. If you have evidence left such as with a dealer that you knew certain problem of the car and kept it hidden from the transaction, then the problem is yours.