Three words no car owner wants to hear: “blown head gasket.” It means major repair and a big bill. But a mechanic’s expertise and precise service manual procedures can cut the cost of this potentially daunting job.

A blown head head gasket replacement can cause coolant to leak into the combustion chamber, leading to overheating. A leaking head gasket also lowers the pressure in the cooling system, which could lead to a loss of engine power. There’s even the possibility that combustion gases could enter the oil port and cause the oil to burn, reducing lubricity and potentially damaging other internal components.

The Heart of the Engine: Navigating Head Gasket Replacement for Optimal Performance

To prevent such issues, a technician should always inspect the mating surfaces of the engine block and cylinder head before beginning work on a head gasket replacement. If the surface is uneven, the old gasket can break while being removed and leave behind a mess that will be very difficult to clean up. Also, make sure to replace all of the cylinder head bolts, as these are one-time-use bolts that should not be reused (in fact, most late-model engines have Torque-To-Yield head bolts that can’t be used on any other part of the engine due to an increased risk of breakage).

One of the most important steps in determining whether or not a head gasket is blown is performing a compression test. This test involves removing the spark plugs and manually threading the compression tester onto each cylinder. When the engine is running, if the compression tester reads 0 psi, the head gasket probably blew. Another way to check is to pop the radiator cap and observe for bubbling in the coolant. This is caused by combustion gasses exiting the engine through the blown head gasket and into the cooling system.