A head gasket is a specialized seal that connects the block of an internal combustion engine to the cylinder head (s). This seal stops combustion gasses from escaping an engine's cylinders, as well as coolant and oil from entering the engine's combustion chambers.
Each engine has between one and two head gaskets, depending on the layout of the engine's cylinders. Inline engines have a single cylinder head and thus a single head gasket. On the other hand, "V" arrangement engines have two different cylinder heads, requiring a total of two head gaskets.
Copper head gaskets were previously quite common on production engines, as were different composite gaskets made primarily of graphite or asbestos. Today, most production head gaskets are made of Multi-Layer Steel (MLS). These gaskets are composed of two to five layers of thin steel that are often coated with a rubberized coating.
The head gasket(s) of an engine is sandwiched between the block and heads using precisely torqued head bolts. Usually, these bolts have a torque-to-yield ratio and stretch when tightened to offer the best clamping seal possible.
Furthermore, the engine's head bolts are torqued in a certain method, which often entails moving outward from the centermost bolts on each head.
How To Know If You Have A Blown Head Gasket
A blown head gasket can manifest a variety of symptoms, which contribute to the need of replacing it. The prevalence of these symptoms varies typically per case and is highly reliant on the particular location of the afflicted head gasket.
Several of the most common signs of head gasket failure are listed below.
Exhaust Releases White-Colored Smoke
White exhaust smoke is likely to be seen if a ruptured head gasket enables the coolant to penetrate one or more of an engine's cylinders.
This is a result of coolant being burned during combustion and then traveling downstream through the exhaust system of a vehicle.
Continuous Coolant Loss
If your car seems to be losing coolant at a consistent rate and there are no apparent leaks, your engine's head gasket is likely at fault.
As a result of the internal nature of a head gasket leak, coolant is usually burned without being visually discharged.
Bubbling In The Cooling System
A slow, steady bubbling of coolant within the radiator or surge tank of a vehicle usually indicates misdirected combustion gases. A specialized combustion gas detector can quickly and easily determine this condition.
A head gasket leak typically presents itself through the exchange of oil and coolant. This often results in a significant shift in coolant conditions. When this occurs, the coolant turns grey or brown in color and seems milky in appearance.
Leaking External Oil/Coolant
In some cases, a blown head gasket may result in a visible coolant or oil leak. This leak will occur at the place where the engine block meets the cylinder head above, although oil may seep all the way to the tailpipe.
Minor bubbles can occasionally be detected in these types of leaking fluids, as small quantities of compression are also expelled.
A blown head gasket is frequently associated with engine overheating. This can occur for a variety of reasons, the most common being coolant loss.
Moreover, combustion gases escaping into an engine's cooling system can contribute to overheating.
Poor Engine Performance
When compression is lost due to a faulty head gasket, an engine's performance almost always suffers.
This is especially true when a head gasket is blown between two separate cylinders, allowing compression to leak through open combustion chamber valves.
In most circumstances, a car with a blown head gasket can be driven, but this is not recommended. Engine performance is directly related to the seal between the engine block and cylinder head(s). As a result, the degradation of this seal will eventually result in a variety of drivability concerns.