Head Gasket Replacement


When your car’s cylinder head is bolted to the top of the engine block, a thin, pre-cut template (usually made of steel plus rubber, teflon or graphite) is placed between the head and block. This is the cylinder head gasket. It forms an airtight seal to prevent leakage or cross-contamination of the coolant and motor oil that circulate (in separate passages) inside the engine block and cylinder head. It also seals off each of the combustion chambers to prevent any leakage of cylinder compression. A head gasket fails or “blows” when it begins to leak due to cracking, burning, melting or warping. These conditions are often caused by pre-ignition or detonation (pinging), overheating or by improper installation of the gasket or a warped cylinder head or engine block.

Failed head Gasket

The result of a failed head gasket is usually an internal between combustion and coolant areas, but can also be a leak of engine oil. If you catch it early, merely replacing the gasket may solve the problem. But as the leak continues to get worse, bad things can happen to your engine. If oil should leak into your coolant, this will reduce cooling efficiency and could cause the engine to overheat.

If coolant should leak into a cylinder or into your oil, it could cause rapid engine wear and eventually ruin the engine because the diluted oil will not be able to properly lubricate the moving parts.If one cylinder is leaking compression, this could cause a misfire as well as a dramatic power loss and an increase in your fuel consumption.If that’s not enough, a blown head gasket can also cause damage else-where. For example, if leaking coolant should find its way into the exhaust stream, this might result in permanent damage to your oxygen sensor or catalytic converter.

Much of the cost of replacing a head gasket is for labor, as the engine has to be partially dismantled to get at the gasket. This explains why the cost will vary quite a bit from one vehicle to another.

Unfortunately, some engines are more prone to head gasket failures than others. This is usually due to the design of either the engine or the head gasket. Pre-ignition and detonation are the major cause of head gasket failures between the combustion chamber and the cooling system. Other causes are corrosive (old or rusty) coolant, defective cooling fan or other cooling system defect.