This is my wife’s car for around town, it has been driving great up till now. I did the head gasket last winter and it surged a bit after that but it was bubbles in the coolant. This time the coolant was down and I filled it and purged the air etc but it’s still surging and undrivable. No steam from the tailpipe or bubbles in the coolant so I am assuming the head gasket is still good. Anyone have the same problem? This car has 250,000 miles on it so far.