Q: When i purchased my used car the check engine light was on . But I was told it was nothing that it would go off . A week later my

If oil and coolant have mixed or are mixing, whether in the radiator or in the crankcase, the cause of those "leaks" has to be identified and repaired first. If you were to diagnose the no start condition, even if you got the engine running, it won’t run long if oil and coolant are leaking "together". I would recommend diagnosing the leak issue first and therefore you should request a leak diagnostic. If overheating the engine caused the head gasket to fail, it is not just a simple matter of putting a new gasket on. Overheating can permanently warp the cylinder head and block so much so that those parts would have to be removed from the vehicle and sent to a machine shop so that they re-condition the head gasket sealing surface. Otherwise,the new gasket will leak (the head gasket sealing surfaces have to be incredibly flat for there to be a seal). If you request the leak diagnostic, which would be performed by a certified Mechanic, dispatched by YourMechanic right to your location, the mechanic will diagnose the leak(s) and let you know of the overall least cost repair strategy to get your vehicle running properly again. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.