Cylinder Head Gasket Functioning and common problems

Cylinder Head Gasket Functioning and common problems

The cylinder block is important as the entire combustion process takes place in this block. However, there should be some seal between the combustion and engine block to prevent the combustion gases from leakage. The head gasket provides this seal

Key Takeaways

The following are the Key Takeaways from this article:

• The Head gasket is a part of the engine that ensures no leakage/loss of pressure at the junction.

• A normal head gasket can be made of steel, but there are several gaskets: solid copper, composites, elastomeric, and alloys.

• Some common problems causing a blown head gasket include high-temperature engine, radiator failure, and eroded lubrication.

• Some common symptoms of a blown head gasket include rough/idle engine start, low-level coolant, white smoke out of the tailpipe, and contaminated lubrication oil.

• Replacing Head gasket can be costly affair depending upon the type and material used in its manufacturing.

Introduction

In a combustion engine, three processes occur at a time. The first process is the combustion, where the air-fuel mixture is compressed, and exhaust gases are produced. The second process is the flow of water-based coolants through the passageways to cool down the cylinder during the combustion process (1). At the same time, the third process includes the flow of lubricants within the engine to facilitate the movement of counterparts within the engine (3).

To ensure that these three functions occur correctly, there should be no leakage or loss of pressure at the junction of the cylinder head and engine block. Therefore, the automakers have designed a head gasket to prevent pressure losses and leakage of fluid/coolant, helping in an effective combustion process.

History of head Gasket

The engine’s head gasket is an essential component and was invented in 1944 by the Va&JZuoen. The head gasket is important as it helps build the required amount of compression and pressure in the engine cylinders. This also helps in generating the required amount of power in the engine. Besides, this part also plays an important role in protecting the coolant. This part did not allow the coolant to enter other parts and maintained the engine’s temperature (2).

The size and dimensions of the head gasket are also evolving with the modernization in technology, but the function has remained the same.

Function of a Head Gasket

The head gasket is present between the engine block and the cylinder head. Along the engine block, the pistons and cylinders are connected, and with the cylinder head, the valves and spark plugs are connected (1).

This part helps seal the internal combustion process and does not allow the fluids to enter the chamber. In early times, the head gasket was composed of iron. But with the modernization in technology, thin layers of steel are used to compose the head gasket.

This is because steel is light in weight as well as it is more sustainable and rigid. The main aim of this component is to produce the required amount of compression after igniting the air-fuel mixture in the combustion chamber (1). As a result, the required amount of power is generated that helps in moving the car in the right direction. Also, this part protects the engine from catching fire as it serves as a barrier, does not let the coolants mix with the engine oil, and maintains the engine’s temperature. Thus, it would not be easy to maintain the engine’s health without this part.

Types of Head Gaskets

Some common types of head gaskets are discussed below:

Types of Head Gaskets

Some common types of head gaskets are discussed below:

Multi-Layer Steel Gasket

This type of gasket is known for its multiple layers of steel interleaved with elastomer. In addition, the face is coated with Viton or similar adhesives for good adherence of the gasket with the engine, increasing the adherence with the cylinder head and engine block.

Multi-layer steel gasket also has an optimized resilience increasing the wear and tear ability of the gasket (3). Due to their increased resilience, most modern automotive models have incorporated multi-layer steel gaskets.

Solid Copper Gasket

Copper gaskets are usually durable due to specialized machining. The O-ringing machined in the gasket incorporates a wire around the cylindrical circumference.

A solid copper sheet is used for manufacturing the wire and gasket itself, making it durable and increasing its ability to wear and tear (1).

Composite Gasket

A solid copper sheet is used for manufacturing the wire and gasket itself, making it durable and increasing its ability to wear and tear (1).

Not only had these gaskets posed health problems due to the harmful chemicals produced during the combustion process in cylinders with composite gaskets (3). But these gaskets were also prone to blowout due to material and conventional design.

Elastomeric Gasket

In the multi-layer steel gasket, elastomer was only used as an adhesive to increase binding with the cylinder block. However, there are special head gaskets entirely made up of elastomer.

It also uses a steel core plate molded with silicon to seal coolant and oil passages. The steel fire rings are also used to fit in the cylinder. Elastomeric gaskets were common in the K-series introduced by Range Rover (1).

O=Ring Gasket

These gaskets are reusable and can be flat-surfaced, leading to increased clamping pressure. An O-ring gasket’s main benefit is its lower surface area, increasing its ability to sustain pressure. In terms of material, O-Ring gaskets are usually made up of steel/copper.

Problems of the Blown Cylinder Head Gasket

Damage to the cooling system and Increased Engine Temperature

The major issue with the head gasket is the abnormal temperature of the engine. A defective head gasket means the seal between the combustion chamber is broken, and the required power is not generated.

Thus, the engine will have to work harder to drive the vehicle. This increases the engine’s temperature, indicating the warning signal on the dashboard (4). Due to the high temperature of the engine, the engine block and the cylinders start expanding, and as a result, the head gasket seal is damaged. The purpose of the head gasket is to restrict the coolants from entering the combustion chamber (2). When the coolant is mixed with the engine fuel, there are chances that the system may catch fire, and the coolant will drop below the level of the engine. This will result in the increased temperature of the engine, and the efficiency will be impacted. In addition, due to the mixing of fuel and coolant, the white color of smoke will be released from the tailpipe. This symptom indicates that the seal of the head gasket has broken and the engine’s working is impacted.

Failure of Radiator

The other major reason for the engine’s damaged head gasket is the radiator’s failure. The radiator is an important part of the engine, and its purpose is to maintain the engine’s temperature by removing unwanted heat from the system.

If the radiator stops working, the excess heat from the engine will not be removed, and as a result, the engine’s temperature is increased. This expands the head gasket and is broken down. The piston’s compression is then reduced, and the required power is not generated. As a result, the car will fail to accelerate and stops after certain intervals. In addition, the engine’s performance becomes idle and rough vibrations and noises are observed from the engine system (4). This happens when engine fuel is mixed with other engine gases and liquids. Thus, it indicates the error of the damaged head gasket.

Erode Lubrication and damaged Catlytic converter.

The other reasons for the blown head gaskets are the damaged catalytic convertor and inadequate lubrication. Due to the lack of lubrication in the engine, the engine parts are damaged, and their performance is affected.

Due to the poor performance of the engine parts, the required amount of pressure is not generated, and the head gasket is damaged (5). Also, the catalytic converter has special importance in the engine. Due to the damaged head gasket, the antifreeze coolants will enter the catalytic converter, generating poison. This will result in a damaged engine, and the engine’s performance will become poor. Also, the milky-colored smoke will release from the engine, indicating that the head gasket is badly damaged and impacting the engine’s efficiency.

Symptoms of a Blown Cylinder Head Gasket

Following are a few symptoms of a blown gasket:

Rough Engine Idle / Engine Misfires

A common symptom of a blown head gasket is rough/idle engine start. As discussed above, the gasket helps maintain an optimum pressure within the cylinder for combustion.

If the gasket is blown/damaged, the engine will lose compression. This will result in an idle/rough engine (2). You can always check for the reason for engine idling/rough start, as different problems in the engine can cause this problem.

Engine misfires are extremely hard on the internal components of an engine. If left unchecked not only will misfires cause harm to the head gasket but potentially damage the engine beyond repair.

If you hear unusual noises, any kind of shudder, or sputter from the engine, it’s best to stop driving immediately and have the engine diagnosed for issues. The reasons for misfires can be multifarious, but it usually can be fixed pretty easily when tended to on time.

Low Coolant Level

Low coolant is another common sign of a blown gasket. A blown gasket will not be able to seal the cylinder, and there is a possibility that the coolant is leaking from the combustion chamber seals

So, the coolant might not be able to revert to the reservoir. It can also be indicated by excessive engine heating as the coolant level decreases. You can always check the coolant level in the reservoir to see if there is adequate coolant. Else, driving the vehicle at high engine temperature can damage the engine seals and eventually seize up the engine.

White Smoke from Exhaust

Engine coolants are usually water-based; when the gasket is blown up, the coolant can be burnt in the engine. Resultantly, the water will come out of the tailpipe in white vapors.

This is a sign that the gasket is damaged and the engine consumes too much coolant. You can visually check the gasket visually when the mechanic opens up the engine (5). If the gasket is damaged, try replacing it soon to avoid severe engine damage.

Engine oil Contaminated

The gasket also avoids mixing up the engine oil and the water coolant. However, if the gasket is damaged, there is a possibility that the water-based coolant will be mixed with engine oil.

This foamy pale oil is built up under the oil filter’s cap. So, if you suspect gasket damage, the first step should be to check if any pale oil paste is built up under the filter cap. It is a sign that the engine oil is contaminated and needs to be replaced to avoid rusting of the internal engine component.

Bad Radiator Clogged Or Fans Not Working

Another possible cause for a head gasket failure is a bad radiator. It actually can cause damage to the head gasket in very much the same manner as low coolant circulation. Due to the radiator’s inefficient performance, the coolant traveling over the engine block will run hot without properly actually having to cool down.

This will essentially increase the stress inside the engine and cause the gasket to warp and bend. You may also possibly smell a burning odor from the coolant due to the double effect of inefficient cooling of the already heating engine.

Thermostat Stuck close

The thermostat is a small valve present in the cooling system that regulates the flow of coolant into the system and its recirculation into the radiator for disposing of the collected heat. If somehow the thermostat isn’t able to regulate sufficient amounts of coolant or has a massive build-up of debris, it can potentially create excessive heat and cause the gasket to be damaged or cracked.

Improper Installation

An engine that’s been refitted with a new head gasket can run the risk of having the same problem again. Oftentimes, while rebuilding an engine it’s never quite possible to assemble back exactly the way the engine was built which more often than not results in decreased performance among other issues.

Rarely though but sometimes while placing a head gasket or when bolting back the engine, human error can lead to improper placement of the metal sheet. An improper installation will not be able to hold the fluid and may soon develop another leak.

Conclusion

To conclude, it can be said that the gasket might not seem like an important engine component, but it functions to seal the engine block and cylinder. So, the combustion process can take place effectively without reduce in the pressure and leakage of coolant from the engine. There are different types of gaskets in the engine depending upon the engine type and model of the vehicle. For example, suppose you face symptoms of a rough engine, low-level coolant, or contaminated lubrication oil. In that case, there is a chance of a blown gasket that should be resolved at the earliest to avoid any severe engine damage.