I was at the petrol station on Friday July 18th and I was putting in oil and the oil cap is coved with white sludgy water and oil. Clearly my head gasket has blown. I was driving the car and drive home from the patrol station and the car was running fine, no loss of power or anything. ( I have not started the car since I got back from the patrol station). Because the car was still running ok there seems to be little to no damage. I need someone who can advise me on what it is going to take and cost to fix the car.