Your car hasn’t worked properly lately, so you decide to take it to a car service center. Once there, after a thorough inspection, the mechanic tells you: “You have a blown cylinder head gasket”.
What is a cylinder head gasket?
Your engine is divided into two massive metal blocks, the engine block and the engine cylinder head. The engine block is the one that houses the crankshaft and the pistons, and the cylinder head houses the intake and exhaust valves and the camshaft (in some cases several camshafts) that moves these valves.
You may have heard of the lower crankcase or just the crankcase, popularly we call it the oil bath, the crankcase is part of the engine block and is the place where the oil is stored.
The cylinder head gasket is located between the two pieces of metal mentioned above, sealing the block and making it behave as a single piece.
Your engine is divided into two massive metal blocks, the engine block and the engine cylinder head. The engine block is the one that houses the crankshaft and the pistons, and the cylinder head houses the intake and exhaust valves and the camshaft (in some cases several camshafts) that moves these valves.
You may have heard of the lower crankcase or just the crankcase, popularly we call it the oil bath, the crankcase is part of the engine block and is the place where the oil is stored.
The cylinder head gasket is located between the two pieces of metal mentioned above, sealing the block and making it behave as a single piece.
The cylinder head gasket plays a crucial role in the operation of the engine. It seals the engine, keeps compression in the combustion chambers and prevents oil or antifreeze from leaking into the engine or inside the combustion chambers.
It must withstand heat of hundreds of degrees (even 800 degrees) and at the same time friction from the two metal blocks, which due to temperature differences, change their shape constantly and put pressure on the gasket.
Many of today’s engines are made of various materials, there are engines that have a lower housing made of hard plastic, aluminum engine block and maybe cast iron cylinder head. Different materials behave differently at extreme temperatures and here comes the role of the cylinder head gasket. It makes the engine all in one piece.
Why does the cylinder head gasket fail?
The interior of the engine is not a pleasant environment, the engine runs in extreme temperature conditions. If the heat exceeds the normal combustion conditions, excessive heat can blow the gasket. When the engine is very hot, the engine block expands too much and the result is a burnt cylinder head gasket.
During the combustion process, temperatures of over 800 degrees can be reached. The oil and antifreeze have the role of taking over some of this heat and keeping the whole set in optimal temperature conditions.
When they no longer do their job properly and the engine has overheated, the cylinder head gasket is the first part to be exposed and be affected, reaching the point of losing its properties and implicitly not fulfilling its role. A blown cylinder head gasket will destroy your entire engine if it is not replaced.
What are the signs and symptoms of a blown cylinder head gasket?
A burnt cylinder head gasket will allow the antifreeze to reach the combustion chamber. Why is this happening? The antifreeze circulates inside the free engine block, cooling it, through some channels.
Imagine these channels as the veins of the human body. The liquid moves constantly and takes over all the heat of the engine and with the help of the radiator it is cooled and then returns to the engine and this cycle always continues while the car is running. These channels are interrupted only in one place, in the cylinder head gasket.
The gasket has holes on its surface that allow the liquid to move without stopping , from the engine block to the engine cylinder head. When the gasket is blown , the channels will stop working properly and the liquid will escape through there, reaching the combustion chamber, but it will also come out of the engine.
The most common signs of a blown cylinder head gasket are overheating of the engine due to a radiator that does not work in normal parameters or antifreeze being present in the oil. These two symptoms are the most common but are not necessarily due to a blown cylinder head gasket, it would be best to leave a diagnosis to a specialist.
What happens if I drive with a blown cylinder head gasket?
Drivers often ignore the signs of a blown cylinder head gasket due to the very high repair cost, especially if the cylinder head gasket is blown due to a cracked or oval cylinder head.
If you continue to drive with a burnt cylinder head gasket, you may cause severe engine damage. For example, this can lead to damage to the catalytic converter, large leaks of engine oil that would lead to serious engine damage due to lack of lubrication and of course overheating of the engine.
As I said above, a cracked cylinder head may be to blame. Let’s talk more about the symptoms of a cracked cylinder head. The cylinder head is a key component of an internal combustion engine. In other words, if you drive an electric car, you are happy, you got rid of the cylinder head. Now,let’s go back, without the cylinder head no vehicle with internal combustion will be able to work, because it deals with the combustion process and then the starting of a vehicle.
The cylinder head is mounted above the cylinder to create a closed space between the top of the piston and the inner walls of the cylinder. It is usually made of cast iron or aluminum alloys.
The cylinder head also has holes for water circulation to help cool the engine. In the lower part the cylinder head is flat for the perfect sealing of the engine block, this sealing is made by the cylinder head gasket.
Symptoms of a cracked or oval cylinder head
If you have a new car, you should not worry that the cylinder head will be cracked or oval, but this does not mean that it would be impossible, there is a pretty small chance that a new car will crack the cylinder head. The symptoms of a cracked cylinder head can be of several types, including:
- oil leak: there is oil inside the cylinder head, once the cylinder head cracks, the oil will start to flow. You can tell in the first phase if you find an oil stain under the car or in some newer vehicle models, when the cylinder head is cracked and there are oil leaks the check engine light will light up on the dashboard.
- coolant leakage: as in the case of oil leaks, you will be able to see traces of liquid under the car, if these leaks are accompanied by the engine temperature indicator, then there are quite high chances that the cylinder head is cracked
- poor engine performance: when a cylinder head is cracked the engine will suffer a lot, because it will no longer be able to form a complete seal for efficient combustion. If you feel that the vehicle is struggling to climb a slope or it doesn’t move smoothly from a traffic light , in other words the engine performance is poor, then the cause could be a cracked cylinder head.
How do you know that the antifreeze gel gets into the engine?
- white smoke released from the exhaust;
- excess water flowing from the exhaust (you should worry about the water flowing from the exhaust pipe only if this symptom also appears with white smoke, because in the case of many new cars, the particle filter in the drum transforms the exhaust gases into water and you will notice small drops of water coming out of the drain, but not white smoke);
- water bubbles in the radiator and in the antifreeze tank;
- the oil foams;
- the engine overheats all the time.
As I said above, the cylinder head gasket keeps the antifreeze and oil inside the engine, so a burnt gasket will let the oil and antifreeze drain on the outside of the engine block.
You can also notice a decrease in the car’s performance, because the pressure in the combustion chamber will decrease and the car will not accelerate as before.
If you have a blown cylinder head gasket, stop driving. Put it on a lorry and head to a car service center. The repair is not expensive and the gasket is not costly either Always choose an original gasket.
In unfortunate cases, when fixing to the cylinder head, the car’s timing belt or even the water pump must be replaced, so make sure that the repair is done according to the book.
How do I not blow the cylinder head gasket?
Make sure the antifreeze level is always within normal limits and if you notice that the car gets very hot, pull to the right and let it cool. If the car continues to overheat, it must be inspected in detail and the problem removed as soon as possible.