A cylinder head cracks under intense pressure and extreme conditions. The head is situated at the end of the engine at the top, and it helps seal the combustion chamber, where the engine makes power by burning fuel. Spending on a cylinder head repair can be a costly affair, which is why buying a new one is the most logical solution for the same. Here we will learn about the five symptoms of a cracked cylinder head.
What Causes a Cracked Cylinder Head?
Before we look at the cracked head symptoms, let us understand in detail what causes the head of the cylinder to crack:
1) Overheating:
The combustion engines located in the internal parts heat up quickly. Their design is such that they can contain tiny, controlled explosions. In the combustion process, thermal energy is used up instead of being converted to kinetic energy that can power the vehicle.
This is the most important cause of a cracked cylinder head. When the engine overheats, its components can experience stress beyond the threshold of heat it was designed to contain. As most of the heads of the cylinder are made of aluminum, they can crack or warp when the engine becomes very hot.
There can be various reasons for the engines of cylinder heads to overheat. Most of these are because its cooling system could have a failed component.
2) Air in the Cooling System:
Another reason for a cracked cylinder head can be the air present in the cooling system. It can allow hot spots to form where one side of the engine has heated more than the one the temperature sensor measured. This is because heat cannot be transferred as effectively via air as via a liquid. If the air is confined to a spot far from the coolant temperature sensor, then the latter may not be able to gauge the hot spot. This is why you may not even realize your car has heated up until the damage has already been done because of your cylinder head. Also, if the coolant system experiences an air leak, it can reduce pressure. Liquid coolant is more capable of boiling at a lower pressure.
3) Failed water pump:
This is the third cause of a cracked cylinder head. Failure of the water pump will result in the coolant being unable to circulate properly through the engine. So, even if the radiator's coolant is cold, it will be hot in the head and block water jackets. Without a pump, the coolant can only circulate through natural convection, which is quite slow when it comes to removing excess heat before the engine overheats and results in a cracked cylinder head.
4) Failed thermostat:
A failed thermostat may result in you having to think about your cylinder head repair or purchase. When combustion engines run at the operating temperature they were meant to, they are the most efficient. The normal operating temperature of an engine is around 190 to 210 degrees Fahrenheit. If the engine runs below this, its emissions, fuel consumption, and wear increase.
A thermostat keeps the coolant away from the radiator until it reaches the engine's target temperature. Once the target is achieved, the thermostat permits the coolant at ambient temperature to enter the engine and help cool it until the thermostat becomes cold enough to shut off. This is an ongoing cycle when the engine is running and can be affected if there is an issue with your cylinder head.
However, if the thermostat is stuck when it's open, your vehicle will likely run cold. This is because the coolant of the entire system is going through the radiator the entire time, and it does not get the chance to warm up entirely. This can lead to your cylinder head cracking.
On the other hand, if the thermostat is stuck when it is closed, your vehicle's engine will overheat quickly. The coolant becomes hot and does not have an outlet to cool down.
5) Coolant leak:
If a lot of your coolant leaks, you will not have enough left to cool your engine. Before it begins overheating, you can lose quite a bit of coolant. It is good practice to check the overflow reservoir and the radiator regularly to ensure you have enough.
If you notice your coolant leaks, you should consider changing your radiator cap, as it can eventually lead to cracked head symptoms. Also, remember that not all coolants that leak can be seen.
Cracked Cylinder Head Symptoms
The symptoms of a cracked head will become very obvious in extreme cases, even though a minor crack may likely go unnoticed. These are the five most common symptoms to look out for to know if you need a cylinder head replacement:
1) Oil Leak:
The head of a cylinder contains oil. In the event of a crack in the cylinder head, the oil is likely to begin leaking. When this happens, the oil light on your dashboard will turn on, indicating low oil pressure. In this case, open the hood and watch out for the oil if it is near the cracked cylinder head.
At times, the oil leakage is internal. In such instances, you might not see a puddle of oil but blue smoke emerging from the exhaust instead.
2) Coolant Leak:
Even though a coolant leak can be the cause of the cylinder heads cracking, it can also be a symptom of the same. If the signs of a cracked head are quite severe, then you are likely to have coolant leaking from it along with the oil.
This will then cause your vehicle's engine to overheat, as you will see on your car's dashboard. In instances of internal coolant leaks, it may seep into the combustion chamber or the oil passages.
You must check your coolant level regularly. Do not drive when you notice a coolant leak or its levels dropping quickly; you will have to think of a cylinder head repair.
Some engines sometimes allow the heater to act as a tiny radiator. However, how effective this method is depends on the heater's core and how the cooling system navigates it.
3) Poor engine performance:
One of the first symptoms of a cracked cylinder head is a loss of engine power. If cylinder heads crack, the air that is compressed in the combustion chamber is escaping. You will notice your engine running slower when this happens.
4) Smoke from engine:
This is one of the rare symptoms of a cracked cylinder head, but the big cracks will let the coolant seep into the combustion chamber and cause the engine to give off white smoke. Also, when the oil begins to leak, it can come into contact with the components of the hot engine, which can also cause this smoke. This is a clear cracked cylinder head symptom. When you see the white smoke, you might have to think of the cracked cylinder head repair.
These are instances that can cause a cracked cylinder head.
5) Engine misfire:
This is related to the third symptom of the cracked cylinder head. If the crack is severe, the mixture in the combustion chamber can result in a misfire. This means the mixture in the chamber will not burn as it should. Or your engine may give up as you drive, and you have to try to start it repeatedly.
Cracked Cylinder Head Repair Costs:
The cost of repairing a cracked cylinder head can be determined after looking at the vehicle model and the make of the cylinder. It will surely cost you $500 at least, which also factors in the costs of parts and labor.
If you have to replace the entire head, you will have to pay an average of $200 to $300 for the parts. The labor costs will come up to $100 per hour. Hence, the total is nearly $500 for replacing a cracked cylinder head. This cracked cylinder head repair cost is reasonable considering the head is made of aluminum, which is the case in most cars. However, if the head of the cylinder is not easy to access, then labor costs can go up significantly.
If you have a more expensive or older vehicle, your new head may be made of iron, which is more costly than aluminum. In this case, the parts for the cracked cylinder head will cost $500. The labor may also include more hours for this job to be done properly. So you can look at spending $1,000 for a cracked cylinder head repair on an iron-made cylinder.
However, if you were to get a replacement for the cracked cylinder head, it would cost you less than repairing it.
Conclusion:
As we mentioned earlier, the cost of repairing the head is more than buying a new one because there is no point in fixing a head whose lifespan is about to end. The cracked cylinder head will end up cracking consistently every time you get it fixed, eventually proving more expensive than just replacing it. So if you are facing engine block car repair costs and the issue of the head being cracked, you can purchase a remanufactured head from us at Allied Motor Parts at the same cost. This new head will also last you longer and save you the trouble of consistent repairs.
