Head Gasket vs. Valve Cover Gasket: Difference Explained
A clear conceptual breakdown of the head gasket vs. valve cover gasket will help you to understand and maintain your car properly for a longer period without any significant hassles related to these two gaskets.
In this article, I’ll explain in detail the differences between these two gaskets. I’ll also discuss the symptoms and reasons for a faulty gasket and what consequences you’ll face having a bad one.
Head Gasket vs. Valve Cover Gasket
In an internal combustion engine, a head gasket is required to provide a seal between the cylinder head(s) and the engine block. On the other hand, a valve cover gasket protects cylinder head hardware and ensures that no oil can escape from the engine.
In an internal combustion engine with a water cooling system, there are three types of fluids traveling between the cylinder head and the engine block. They’re combustion gasses, coolant in the passages of the cooling system, and lubricating engine oil.
The purpose of a head gasket of an internal combustion engine is to seal the combustion products within the engine cylinders. It also prevents the leaking of coolant or engine oil into the engine cylinders.
The valve cover gasket is typically made of rubber, cork, or plastic to create a leakproof seal and acts as a two-way barrier. During the operation of an internal combustion engine, when a hot oil shower for lubrication is required, the valve cover gasket works to ensure safety.
It also prevents small particles and debris from entering between the cylinders and the pistons.
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How Many Gaskets Are Present in the Engine of a Car?
Gaskets provide a seal between two surfaces of an engine. They also ensure balanced internal pressure, prevent dirt and debris from entering the engine, and keep important liquids and fluids inside the engine.
The cylinder head gasket, oil pan gasket, intake & exhaust manifold gaskets, pump gasket, valve cover gasket, and timing cover gasket are some of the most important gaskets present in the engine of a car. Let’s get a clear idea of each of them.
- Cylinder Head Gasket
The cylinder head gasket is generally made of asbestos and steel or asbestos and copper. It ensures that there is no leaking of coolant and engine oil. A head gasket also seals combustion products within the engine cylinders.
- Oil Pan Gasket
Oil pan gaskets are generally made of synthetic rubber, cork, or fiber sheet with latex rubber coating. It seals between the engine block and the bottom of the oil pan.
- Intake & Exhaust Manifold Gaskets
These two gaskets are generally made of embossed steel or metal-encased asbestos. The intake gasket ensures the presence of a proper amount of oxygen in the fuel mixture. It also keeps the air inside the engine cylinder by preventing the leaking out during combustion.
The exhaust gasket stays between the exhaust manifold and the cylinder. It prevents harmful smoke from running away from the exhaust into the interior of your vehicle and before the tailpipe.
- Pump Gasket
The pump gasket is typically made of various types of materials such as asbestos, karropak, and more. They’re made in such a way as to withstand oil, petrol, water, and antifreeze liquids. A pump gasket seals the engine block and water pump together.
- Valve Cover Gasket
Valve cover gaskets are generally made of cork, rubber, or plastic. The function of this kind of gasket is to ensure the safety of the engine by creating a leakproof seal during engine operation.
- Timing Cover Gasket
It is designed in such a way that it can seal the front of the engine. It provides a seal between the engine block and the timing cover and can seal coolant and oil.
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What Is the Difference Between a Head Gasket and a Valve Cover Gasket?
The head gasket and the valve cover gasket remain in the upper part of an internal combustion engine. Though both of them contain some analogous parts, there are several differentiating factors in terms of materials, durability, replacement cost, and fitting location.
- Materials
The cylinder head gasket is generally made of asbestos and steel or asbestos and copper.
Valve cover gaskets are generally made of cork, rubber, or plastic.
- Durability
A head gasket can last for many years over a journey of at least 100,000 miles. They tend to crack and become harder as time passes as rubber is used to make and design a head gasket.
The valve cover gasket is designed in such a way that it can extend the overall lifetime of a vehicle.
They go bad if the cylinder head wraps or cracks and the motor are working at a very hot temperature for a long time.
- Replacement Cost & Difficulty
It isn’t that difficult to change a head gasket. You need to spend somewhere between $200 and $700 for the replacement of a head gasket which consists of two costs.
A new head gasket costs around $50-$150 and you need to pay somewhere between $150-$450 for the service of a mechanic. Services from an experienced mechanic will cost more in the replacement.
Replacement of a valve cover gasket isn’t always a costly repair. In most cases, the whole replacement process costs somewhere between $250 and $350.
A new valve cover gasket will cost you about $100 and you need to pay about $150-$250 for the replacement services. As always, services from an experienced mechanic will cost more.
- Fitting Location
A head gasket stays tightly between the cylinder head and the engine block. On the other hand, a valve cover gasket is between the valve cover and the engine.
What Causes a Bad Head Gasket and Valve Cover Gasket?
The cylinder head gasket and the valve cover gasket are integral parts of an internal combustion engine for proper functionality and safety. They generally last for years if maintained properly but some conditions and practices can cause premature failure of both of them.
Let’s have a look at some reasons that can make your head gasket and valve cover gasket bad in a short period.
Head Gasket
- Overheating
- Pre-ignition
- Detonation
- Snappy Changes in Temperature
- Wrong Installation
- High Mileage
- Rough Maintenance
Valve Cover Gasket
- Loose Bolts on the Valve Cover
- Brittle or Cracked Gasket
- Damaging Valve Cover
- Poor Replacement Servicing
- Clogging in Suction Jet Pump
- Improper Maintenance
What Are the Signs of a Faulty Valve Cover Gasket and Head Gasket?
It’s important to know the signs of a faulty head gasket or valve cover gasket. Driving with any one of them having issues performing properly isn’t a wise decision and may lead you to some dangerous engine problems.
Let’s talk about some signs of a faulty head gasket and valve cover gasket so that you can identify easily whether any of them goes bad.
Head Gasket
The most noticeable sign of having a faulty cylinder head gasket is overheating as a shortage of coolant takes place in the engine cooling system. The engine oil may be discolored because of the mixing of oil and coolant. A further indication of a faulty head gasket is blue, gray, or white smoke with a lack of power from the engine.
Valve Cover Gasket
First, look carefully if there are any oil leaks as a faulty valve cover gasket is responsible for an oil leak in your car. You may also notice a burning smell as oil leaks from the car and lands on the car and other parts.
What Will Happen if Either of the Gaskets Goes Bad?
As both the head gasket and valve cover gasket play important roles in the engine, their malfunctioning can be easily realized. The following are some of the consequences that you’ll face if either of the gaskets goes bad.
Head Gasket
- Overheating of the engine
- White smoke from the tailpipe
- Low coolant level due to coolant loss and mixing with engine oil
- Rough engine detonation or knocking
- Contamination in the engine oil with coolant
- Loss of power
Valve Cover Gasket
- Oil leakage
- Smoke will come from the engine
- Misfiring of engine
- Low level of engine oil
- Rough idling of the engine
