The head gasket is an extremely important engine component, so any indication that it's not in good shape should prompt you to get it repaired.

According to the automotive website CarsDirect, the head gasket is a mechanical component sealing the cylinder head—home to the engine valves—to the engine blocks, which includes the pistons and crankshaft. Louetta Automotive of Cypress, Texas, says the purpose of the head gasket is to provide a tight seal for the combustion and compression processes and to prevent antifreeze and coolant from getting into the cylinders. According to the automotive website Autos.com, the constant pressure on the head gasket over time will cause it to be warped or develop cracks.

It can sometimes be difficult to determine whether the head gasket is the source of your troubles. The AGCO Automotive Corporation of Baton Rouge, La., says the trouble caused by the head gasket will vary depending on where the component fails, and other parts might cause the same symptoms if they break down.

A misfiring engine or rough idle might point to a failure of the head gasket between two cylinders, as compression is leaking from one cylinder to another. The gasket can also fail between a combustion chamber and cooling system, causing the engine to overheat. A breakdown between the coolant and lubrication systems will cause coolant to mix with oil. The gasket may also develop exterior failures through which coolant and oil will leak.

In the most severe cases, a blown gasket can cause a sudden loss of power in the vehicle. Getting the issue repaired is essential at this point. Other signs will hint at head gasket trouble before it gets too pressing, however.

The most common sign of a blown head gasket is exhaust smoke. White smoke indicates that your car is burning coolant that is leaking into the cylinders. A similar problem is indicated by blue exhaust smoke, though this is a sign of oil leaking from the gasket. The exhaust pipe may also be emitting excess moisture or dripping water.

Another indicator of head gasket trouble is the presence of coolant in oil, which CarsDirect says can negatively affect the lubricating qualities of the oil. Check your dipstick for a milky substance, signs of water, or oil that is brown and bubbly in consistency.

Starting the car and observing the engine will also allow you to spot problems that may be a result of a blown head gasket. Check the coolant reservoir to see if bubbles are coming from the engine inlet. According to Autos.com, removing the radiator or overflow cap and revving the engine is a good way to check for a head gasket failure; if bubbles appear continuously, it may indicate that the gasket is leaking coolant.

The AGCO Automotive Corporation says a mechanic can pinpoint gasket trouble using a hydrocarbon cooling test. This test analyzes the fumes from the coolant in the radiator to determine whether hydrocarbons are present, as this is often a sign of a head gasket failure.

The head gasket may also be having problems due to warping or corrosion. Overheating caused by a loss of coolant through a blown gasket can further damage the component through the emission of corrosive coolant gases. Fuel with too low of an octane level can also cause some vehicles to experience elevated cylinder head pressure, leading to a knocking or pinging sound.

Repairing the head gasket is a complex and often expensive job due to the work required to access the component. AGCO suggests taking some preventative steps to avoid damage to your head gasket and prolong its life. Coolant should be of a proper type for your vehicle, mixed with distilled water before addition to the engine, and replaced whenever its pH falls below neutral. Drivers should also address any overheating or pinging issues without delay.