A head gasket can last over 100,000 miles on a car that is maintained regularly, but a blown or damaged gasket should be replaced immediately. Common signs of a blown or damaged head gasket include engine overheating, frequent coolant loss with no sign of a leak, white smoke emitting from the tailpipe, loss of power, and milky discoloration in the oil. A head gasket is one of the most important seals in your race car, so fix a leak at the first sign of a problem to avoid costly repairs down the road.