6 Cracked Cylinder Head Symptoms With Solution And Repair Cost

​A cracked cylinder head can result in various problems with the engine due to their close proximity to pistons responsible for fuel and air compression inside the combustion chamber. If damaged, they have to be replaced or repaired immediately they are discovered.

It may be a bit difficult to identify a minor cylinder head crack because the engine would continue to function normally. As the crack increases, you would begin to notice the symptoms and experience various problems with your engine.

Diagnosing a cracked head requires regular examination of your engine. If there is a coolant leak in the combustion chamber as a result of a cracked head, it may be difficult to find your crack in a long time. This occurs when the crack is present between the parts on the outer surface of the cylinder head and the cooling jacket.

A very large leak of coolant could lead to terrible problems with the cylinder, causing major damage to the bearings.

If the combustion gases from the engine are released into the crack, they may find their way into the exhaust system and give rise to contamination of the oxygen sensor.

However, a head crack does not indicate that your it needs a change. You should see a mechanic for a full diagnosis of the problems associated with the engine and act accordingly.

Why Cylinders Crack?

A cylinder head cracks due to the actions of the various forces around it. Such forces include high temperatures or a sudden change in temperature from cold to hot or vice versa, and loss of coolant.

Cylinders made of aluminium will crack faster than those made of iron because the expansion of aluminum in the presence of heat is twice as high as that of iron. This expansion eventually causes a deformation of the edge making it incompatible with the iron cast.

Symptoms of Cracked Cylinder Heads

There are several symptoms associated with cracked cylinder heads. Here are some of them which you’ll notice as the crack begins to expand

1. Smoke

A smoking car is never a good sign. The release of smoke due to a cracked head is a rare occurrence which only happens if the cracks are extremely large, allowing the release of exhaust gases from the cylinder head which comes out as smoke from the engine. When you notice smoke from the engine, it is very vital not to ignore.

With immediate effect, you need to change your cylinder immediately to prevent further problems from occurring.

2. Oil Leakage

Oil is needed for the general functionality of the internal combustion engine. It is no surprise then that the head of the cylinder contains oil. When there’s a crack, the oil present in the head will be released from the crack. Trails of oil spill will be evident as the car moves from one destination to another.

Now, how much oil can be lost from a cracked cylinder head?

The rate of oil flow depends on how large the crack is. If this happens when driving, the oil light would be turned on which would indicate a problem with the oil.

There are several other reason why oil leakage occurs, this is why it is important to verify the oil leak is from the cylinder and not any other source.

3. Poor Engine Performance

Problems which are allowed to persist in a car engine, especially in-depth systemic problems will carry along grave consequence.

This is why after the crack lasts a while, you would notice that your car begins to malfunction, stopping on the road while you’re driving, or running out of steam so fast and other accompanying problems.

More of these malfunctions will build up over a period of time. These malfunctions are a consequence of a cracked cylinder.

When compressed air escapes from your combustion chamber, your car would become unable to go as fast as it used to. Being overtaken by cars on the road and frequent breakdown will persist. This signifies a weaker engine. When you notice this problem, call an engineer immediately to have your engine checked.

4. Coolant Leakage

Loss of compression affects a car engine's coolant negatively. Compressed air can escape due to damaged cylinders in the internal combustion engine.

The car engine's coolant begins to leak after severe damage over time on the cylinder head in the engine. Sometimes, there's usually coolant leakage accompanied by oil leakage as a result of a large crack.

This results in the overheating of your engine which will be indicated on your dashboard. When this happens, open your hood to check for the amount of coolant available.

Also Read: Bad Radiator Cap Symptoms

5. Engine Misfire

When your engine begins to seize for a short period and picks up the pace almost immediately, it is an indication of a severe problem present. This is what is referred to as the engine misfire.

The engine misfire occurs as a result of the poor engine performance and a declining engine. If the cylinder head is not repaired and replaced, even after compressed air leaks out of the combustion chamber, the engine is prone to shout down.

A crack in the cylinder can lead to  this problem. However, most times this happens when the crack in the engine is severe. The inadequate amount of mixture in the combustion chamber would cause the engine to stop working every time you’re driving.

6. Milky Engine Oil

This is one of the easily recognized symptoms of a crack in the  cylinder. It specifically happens when the coolant finds its way into the combustion chamber through the crack.

It passes through the pistons close to the cylinder head and enters the engine oil, turning it milky white. This symptom can be easily noticed by examining the color around your dipstick.

Solutions To Cracked Cylinder Head

Compared to some components of the car, the cylinder should not necessarily be replaced if there is a crack on  the cylinder head. In essence, not all cracked heads need to be replaced. Most cracks on the cylinder head nowadays are being repaired quite easily.

In car maintenance and repair, there's more risk involved in repairs compared to buying new engine components. This is to say that there is a high risk involved in repairing a crack head. But compared to paying for a new cylinder head, repairing a cracked head is much cheaper.

  • Most cracks that occur in cylinder heads can be easily fixed by pinning if they're small enough and haven't reached a severe stage.
  • Severe cracks in cylinder heads made of aluminum are usually repaired by welding. A special type of welding known as Tungsten Inert Gas (TIG) welding is used.
  • In the case of iron cylinder heads, the TIG welding cannot be used because it is much thicker. Instead, flame spray or furnace welding is used to cover the crack.

Cracked Cylinder Head Repair Cost

The cost of repair will involve payment for a  new crack head, payment for services rendered by automobile repair engineers, and additional charges if necessary.

Herein, the rate of the cost to repair a cylinder head varies depending on the professionality of the engineer hired, the type of vehicle affected, locality and location and the model of the cylinder head.

The least possible cost of repair for repairing the cracked cylinder head is $500 including the cost of labor and purchased parts. Sometimes, the prices can skyrocket to be as high as $1000 depending on how much your repair engineers charge for labor.

Some engineers charge up to $100 an hour for labor, but this only works when the cylinder head is made of aluminum which has cheaper parts and is easier to fix.

When the cracked head is made of iron, it takes more time to repair and the parts are generally more costly. Repair of iron heads should be close to or a little above $1000.

Tip: A cracked head cylinder is one of the major damage which has the ability to weaken a car's engine. Although, the cost of repair is quite expensive and the search for the particular brand or model suitable for your car model maybe tedious, it is advisable to change crack heads than repair.

This reduces future cylinder and engine problems and is more cost effective if the long run is to be considered.


Constant periodic maintenance of cars will prevent majority of the engineering problems which come with car problems and breakdowns.

Even if the problem is inevitable, as over time, machine in general wears and tears; there will be instant recognition of the problem before it persists and cause severe damage to the engine as whole.

Cracks arise from little maintenance and can cause more problems if allowed to persist over a period of time.

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