Cylinder Head: Detailed Description (Expert Guide)


The top cylinder is the component that closes the combustion chamber in the engine. It restricts gases from escaping and provides safe space for combustion to take place within the cylinder.

The top cylinder is also called a cylinder head. The cylinder head is the unit that closes the combustion chamber, while the top cylinder is the outer layer of a cylinder head. You can use them interchangeably.

The cylinder head sits on the cylinders over the engine block; it seals the top of the cylinder establishing the combustion chamber. This joint is closed by a gasket. In the course of this article, we would also talk about the cylinder head gasket.

How does the cylinder head work?

Vehicles with cylinder heads have engines that make use of cylinders as combustion chambers for burning fuel. Electric cars do not make use of cylinder heads as they do not burn gasoline.

The cylinder head is constructed in such a way that it has two separate grooves/pathways that allow the passage of coolant and oil. On the one hand, oil flows to lubricate the valve and the camshaft, while the coolant flows to reduce temperature.

While the cylinder head allows the flow of these liquids, it also prevents them from getting into the combustion chamber as that will be bad for the engine in more ways than one.

What is the cylinder head?

Top cylinder

The Cylinder head is the radiative point of an engine. The cylinder head is where the Top Dead Center level of a four-cylinder engine and the top cylinder unit sit. It is where the valve works.

The top dead center means the topmost point of the piston in the cylinder of an engine. It is the place from which ignition system capacities originate, and it regulates the firing order.The cylinder head alongside the piston forms the combustion chamber. It contains a unit that differentiates the valve and the piston known as the cylinder head gasket.

We will explain the Cylinder head gasket in the course of this article. Without the cylinder gasket, the valve can get broken and pierce the piston.

Furthermore, the firing order will no longer be intact, and this can lead to misfiring. You can get to know more about misfiring in our previous article misfiring engine.The cylinder head is a sensitive place where every function of an engine meets to produce sound. Here is where you get your intake, power, compressions, exhaust discharge. It is a critical part of an engine.

What are the components?

 Components of a cylinder head

The cylinder head contains both internal and external components. The internal include:

  • Valves
  • Sparkplugs
  • Thermistor
  • Camshaft
  • Lubricant
  • Coolant

The external component includes:

What is the function?

  • To balance the elements of compression, power, intake, exhaust for them to function efficiently.
  • It reduces the heat formed by the engine and therefore brings about cooling.
  • Provide the structure for various components such as valves, spark plugs, etc
  • It allows the flow of coolant, oil, and combustion gases

Cylinder misfiring and what it affects

Misfire occurs when there is incomplete combustion in the engine cylinder or when the combustion chamber is malfunctioning. Misfire indicates that the emission from the engine is abnormal. For your engine to fire the cylinder, it depends on three main components: fuel to burn, oxygen to aid burn reaction, and a spark to make it move.

A bad spark plug is the number one reason for engine misfiring. However, when there is an issue with the cylinder, it can cause misfiring. For instance, if the cylinder breaks and coolant flows to the combustion chamber, misfiring will occur.

This scenario will cause the spark plug and valve not to function. The valve is to open the fuel and close it.

Cause of misfiring engine

Water and engine oil is an uninvited element in the combustion chamber. You don’t need them to come into the units where compression, intake, power, and exhaust sit. When these elements get into the combustion chamber, it will cause problems to the system.

These problems will obstruct the functionality of the valve and spark plug. you can read our well-written article on variable valve timing explained by an expert.

When water, the coolant, gets into the chamber due to its high density, it would not burn. Since water is resistant to power, it remains. The water then gets into the mouth of the spark plug, and it destroys the plug that causes the misfiring.

What are the signs and symptoms of a bad cylinder head?

  • Overheating
  • Misfiring
  • Irregular Temperature.
  • When the coolant mixes with the fluid and causes incomplete combustion.
  • Your vehicle will not be moving at optimal speed.
  • There will be a shortage of water in your car because coolant is passing inside the fluid.
  • There will be moisture in your vehicle reservoir because the fluid sends some particles to the radiator or reservoir.
  • When the cylinder head has excess tolerance in between the sieve walls.

Can a cylinder head get bad?

Yes, it can get faulty. The level of heat in the cylinder head is usually very high due to the functions at work in it. When there is overheating, the cylinder head is in danger of becoming faulty.

The coolant, engine oil fluid, air, fuel, and compression functions in the cylinder head give it an average temperature level that can allow the engine to function very effectively.

The gasket acts as a regulator that helps the elements not to flow past their boundary. Every part in the cylinder head has a limit to where it flows. Once the gasket gets broken, these elements will flow into areas where it is not needed, and this will cause damage to the cylinder head.

What forms the cylinder head?

The cylinder head comprises the top, the block, and the piston.

  • Aluminum cylinder head: The one for the top.
  • Cast aluminum for the block
  • The piston is aluminum build

What can damage a cylinder head?

  • Overheating affects the gasket that differentiates the two cylinders.
  • When the gasket separates, the elements contained in the cylinder will flow past their boundary. When the parts go past their boundary limit, there will be incomplete combustion, and the cylinder head will malfunction.
  • Insufficient coolant: When there is a water shortage in the radiator, the thermistor or coolant temperature indicates red on your dashboard. If you do not discover this early, the heat increase above the expected temperature, and the gasket will flash or separate. The heat will penetrate the cylinder head because of its aluminum base. Once this happens, the cylinder head is damaged.

What is the cylinder head gasket?

 Top cylinder gasket

The gasket is in between the cylinder that separates the engine block from the cylinder. The gap in between enhances that the valve will not touch the piston with the aid of a timing belt.When the head gasket cracks, the coolant will get into the combustion chamber and cause overheats and misfiring. If the coolant touches the spark plug, it will not conduct.

Functions of the cylinder head gasket

  • It protects the cylinder from oil and coolant flow.
  • This gasket helps the valve not to merge with the sieve.
  • It gives a degree between the engine block and the cylinder. Thereby, it prevents the valve from touching the piston. When the valve and piston make contact, the valve and piston will either get broken or destroy the valve sitting of the cylinder head and some vital components of your vehicle.
  • The design of the top cylinder is designed the same way as the basement of the cylinder head and the engine block.
  • Two fluids pass through the cylinder: the coolant and the engine oil. The area that controls the coolant, the top cylinder gasket, makes sure the line remains on its own. Also, the portion that regulates the engine oil, the Top cylinder gasket, ensures that the line is intact. If the gasket cracks and the two-line meet each other and the two fluids mix, there will be a problem in the system.

Is it better to repair a head gasket or replace it?

 Blown top cylinder gasket

We advise you to replace the gasket. It has no second-hand value. Change the gasket and clean the dirt within that unit, and the engine comes back to life. Furthermore, the impact does not affect the top cylinder itself or either the engine block or the piston. You can also read on How to change a head gasket.

Can you drive a car with a blown head gasket?

When the gasket blows, and only two cylinders are affected in a four-cylinder car, you can drive your vehicle. However, drive your vehicle to a nearby maintenance office to get it fixed. However, your vehicle will be moving very slowly. At this point, you are forcing your vehicle to move, and as a result, it will consume a lot of fuel.

Furthermore, there will be a mixture between the coolant and engine oil because of the separation between the gaskets. This mixture will cause more problems for the car.In other cases, the vehicle will shut down immediately. For instance, when it blows completely, there will be no more compression.

When you start the car, you will have a revolution that the current is not flowing. The power and compression action can no longer merge to perform their function.At this point, you cannot drive your vehicle. You should tow your vehicle to a car technician and have it fixed.

Does a blown head gasket make any sound?

Yes, it does when the coolant is off from the system. It makes a coughing sound.In some cases, the sound could be a result of unrefined fuel. When poorly refined fuel gets to the combustion chamber, there will be some resistance.

Hence, the sound as you accelerate your vehicle. At this point, check your car temperature. Be very conscious of its temperature. The car manufacturer advises that the Normal temperature level should not go beyond 90. Furthermore, if it gets above, then it is dangerous. Take your car for a routine check, the faults could be a water shortage, or the top cylinder gasket is becoming weak.

Can a blown cylinder head gasket ruin an engine?

Faulty gasket

Yes, when the gasket blows, and you did not discover it on time, it can ruin your car engine. The temperature of your engine can become so high.

Furthermore, the engine rings comprising of aluminum will compress. This compression will lead to damage to the engine.The flow of coolant within the sieve ring ward reduces the temperature. However, the coolant is no longer functioning because of the blown gasket. When this happens, the temperature of your engine becomes so high, and the rings will merge. As a result, it can destroy your engine.

What is the primary cause of top gasket failure?

Lack of lubricant is the primary cause of top gasket failure.

How to maintain the cylinder head

  • Always that ensure your lubricant is always at the maximum point.
  • Check the temperature switch regularly to avoid overheating.
  • Always check your coolant level and ensure it is at the maximum point.
  • Ensure your reservoir is at the maximum point. Do not go above the maximum. It can cause the water not to flow, and that will result in overheating.

Conclusion and final words from the expert

The cylinder head is an essential part of your vehicle. To keep it in good shape, ensure to watch your temperature while driving. Overheating is the common cause of its breakdown.

Another cause may be a mechanical fault. For instance, the chains get broken, or the valve went above its initial position. Another role of the cylinder head is to ensure the continuous lubrication of the cylinder. If the cylinders are not well lubricated, smooth functioning of the engine is not possible, which is why it is a vital part of the function of your car engine.

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