While prices vary by location as well as the make and model of the vehicle, the 2014 national average cost to replace a head gasket is between $1,139 and $1,462, according to Repair Pal. Parts for the repair are relatively inexpensive at $55 to $93; however, the job involves a great deal of labor.
As a part of the repair, mechanics generally inspect the entire cooling system. Failure to do so often leads to a recurring problem. The mechanic also inspects the cylinder heads and machines them if necessary. Once inside the engine, they often find additional, yet necessary repairs that add several hundred dollars to the cost of repair.
Head gaskets often fail when engines are overheated. A lack of coolant due to a leak or broken hose often leads to the initial problem. Head gasket failure also occurs due to high mileage and aging of the vehicle. When the gasket fails, the vehicle often runs rough when started, especially on the first start of the day. As the engine expels moisture from the cylinder, the idle tends to smooth. Coolant leaking into the oil gives it an appearance like chocolate milk, and the dipstick sometimes shows an abnormally high level of oil. The car often produces a white smoke from the tailpipe with a sweet antifreeze smell.