Cylinder head gasket
The
cylinder head gasket is located between the engine and the cylinder head and
assumes the most critical sealing function in the engine, preventing engine failure
caused by the fusion of gasoline and water. In general, automotive engine
internal combustion engines use a water-cooled gasoline four-stroke design in
which three circulating circuits, flammable air or fuel mixture, aqueous
coolant mixed with ethylene glycol, and lubricating oil are important. However,
once the materials of the three circulating circuits are mixed together, it
will cause the engine to overheat, the oil burns or the coolant burns.
If the
cylinder head fails, the following series of problems will occur:
(1)
Reduced compression force - The car's power will be reduced or the engine will
be unstable.
(2)
Exhaust gas is forced into the cooling system - causing the oil and coolant to
mix, increasing engine wear and making it susceptible to overheating.
(3)
Leakage of coolant to the cylinder (internal leakage) - can cause exhaust pipe
problems and damage to the catalytic converter. In addition, a large amount of
coolant leaking into the cylinder can also cause hydraulic locking problems,
causing large-scale damage to the engine.
(4)
External leakage - Gasoline and coolant accumulate under the engine.
(5)
Compressive force leaks into the small gap between the engine and the cylinder
head gasket - When the engine is extinguished, these trapped air will run into
the coolant to create air bubbles. If these bubbles are trapped in the engine
cooling temperature controller, severe engine overheating will occur, and the
gap between the cylinder head gasket and the engine will gradually increase.
All of
the above are related to the failure of the cylinder head gasket. Sometimes,
the driver can still drive normally when the exhaust pipe emits too much
exhaust gas until all the coolant is used up, eventually causing the engine to
overheat.
The
cylinder head gasket can be roughly divided into the following four types:
(1)
Multilayer iron cylinder gaskets - the most common modern engine cylinder head
gasket. It usually consists of three layers of iron: the top layer is rubber
surface coating (layer), the contact surface (layer) has wave-stopper
technology, the bottom layer is fully painted and the exterior is partially
painted.
(2)
Solid copper cylinder head gasket - The cylinder head made of solid copper is
extremely durable. However, it requires special O-ring processing techniques to
place a coil around the cylinder ring to fit over the copper.
(3) Composite
cylinder head gasket - Older cylinder head gasket made of asbestos and
graphite. Due to health considerations, the use of such cylinder heads is
gradually reduced.
(4)
Elastic Cylinder Gasket - This cylinder head gasket is typically used in the
Rover Group's K-Series engines. Its cylinder head design is used in the F1
sports car to achieve unprecedented success. However, this design has a
persistent phenomenon that cannot be solved at present, and the cylinder head
gasket cannot cope with the problem of unstable joint surface.
A
pressure gauge or leak test can be used to view the condition of the cylinder
head gasket. At the same time, when the exhaust pipe starts to emit white smoke
or blue smoke, it is time to replace the cylinder head gasket. Although the
cost of the cylinder head is not high, the replacement of the cylinder head is
very time consuming, so the labor cost accounts for 75% of the near cost. In
addition, unmaintained cylinder head gaskets can cause even greater damage to
the engine, which in turn requires higher maintenance costs.
