Ahmad: Salam Alaikum. From what I can gather, possibly your mechanic is not a professional. The overheating of a car engine could be due to other reasons other than what the mechanic has checked so far. The engine could be overheating if the water pump has stopped working. Yes, a leaking head gasket could also be a reason, but then that is not a very costly job. By opening up the engine he has led you bear additional expenses which could have been avoided. Also, what guarantee is there that the second-hand you intend buying and that too from Dubai is going to be in good condition? I feel you are heading for long line of expenses.