What is an Engine Gasket?
Gaskets are designed to provide a seal between two engine surfaces. Engines, by virtue of their material and function, are subject to changes in temperature and pressure while engine parts are subject to movement. As the engine heats up and cools down, it experiences pressure from compression and vacuum, and engine parts expand, contract, move away from each other and are drawn tighter.
Because the engine experiences forces and stress from every direction, the gaskets are heated, cooled and rubbed. A cold gasket reacts differently than a hot gasket, just as a gasket under increased pressure acts differently under decreased pressure. Read on as we take a look at the different gaskets in your vehicle.
The valve cover gasket sits between a relatively thin steel cover, cast aluminum or plastic composite cover and a cylinder head that is cast from iron, aluminum or alloy (mixture of metals or metals and non-metals). When the engine is first started on a cold day, the oil that flows through the system could be 32°F or colder. The gasket, like the head and valve cover, are just as cold. As the engine warms up, the oil, head, cover and gasket warm at different rates.
The heat generated by the friction in the head and engine block heats the oil. As a result, the heat radiated by the block, head and oil heats the valve cover. Over many miles, time and engine heating/cooling cycles, the valve cover gaskets may no longer do their job of sealing and allow oil to leak out.
The oil pan gasket sits below the engine block in the area called the crankcase, named so because that is where the crankshaft resides. It is compressed between the crankcase and a durable steel pan or cast pan. The pan is relatively thinner than the crankcase, which is generally cast from iron, aluminum or alloy. The same physical aspects that affect the valve cover gasket and head gasket affect the oil pan gasket.
Oil resides in the oil pan when an engine is not running and to return to while running. As the engine heats up on a cold winter day, the oil, pan and gasket follow suit. When the engine is turned off and the hot oil returns to the pan, the three cool at different rates. Over time, a stressed oil pan gasket can fail at different times, either under the cold condition, the warm condition or under the moving conditions of the pan against the case.
Intake gaskets can be made from aluminized steel coated in a carbon-based rubber compound, paper bonded to a metal core or molded rubber, the intake manifold gasket seals the intake manifold to the cylinder head(s). High-quality intake manifold gaskets are constructed as one-piece with embossments and sealing beads around each port or runner opening. They must be resistant to decay caused by oils and coolants as well as fuel. The performance of your engine depends upon the quality of the intake manifold gasket.
If the intake manifold gasket fails, coolant can leak out of the manifold. Since the engine is losing coolant, it may overheat because it no longer can properly cool itself. If the issue isn’t addressed in a timely manner, it can cause permanent damage to the engine block and cylinders. Another type of failure is at the intake runner port which is a vacuum leak that can cause rough running, increased fuel consumption and the Check Engine light to come on.
Designed to seal the front of the engine where the timing chain resides, the timing cover uses a timing cover gasket which provides a seal between the timing cover and engine block. This gasket can be sealing coolant and oil.
Over time, the gasket’s sealing material can become scrubbed away due to expansion/contraction cycles and fail, possibly leaking coolant or oil. In some cases coolant may leak into the crankcase, contaminating the engine oil.
If you are experiencing a fluid leak, make an appointment with your professional technician. They’ll be able to diagnose the problem and complete the necessary repairs.
The content contained in this article is for informational purposes only and should not be used in lieu of seeking professional advice from a certified technician or mechanic. We encourage you to consult with a certified technician or mechanic if you have specific questions or concerns relating to any of the topics covered herein. Under no circumstances will we be liable for any loss or damage caused by your reliance on any content.
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