Bad Cylinder Head Symptoms banner

Cylinder head symptoms help you to detect a falling head. The causes of these signs vary and depend on the type of damage. Faulty cylinder head symptoms should not be taken lightly. A damaged head can affect a vehicle’s engine performance, or even reduce its lifespan. Learn about signs that show a bad cylinder head here. We also included a section about how to prevent damage at the end of the article.

Causes of Cylinder Head Problems

What makes a cylinder to become faulty? There are many reasons. The main ones are:

  • End of lifespan
  • Cracks
  • Cylinder head gasket damage
  • Warped cylinder head
  • Worn valve guides and other cylinder head parts

Damaged Cylinder Head Symptoms

Having discussed the causes of cylinder head problems, let us now see about the signs to look out for. The symptoms are divided into categories. There are those that show a cracked head, warped head, porous head, and head gasket wear or damage.

cracked cylinder head symptoms

1. Cracked Cylinder Head Symptoms

Cracks can happen on a cylinder head due to various reasons. Mostly, high temperature causes them. Temperature fluctuations, too, that cause the cylinder head to heat up then cool rapidly. Old age is also another reason for appearance of cracks. If the head is made of aluminum, then the more likely it is to crack. Signs that indicate a cracked cylinder head include:

  • Time- although not a symptom as such, time shows that a cylinder head needs to be fixed or replaced. An aluminum cylinder head generally serves you for around five years, after which it becomes prone to various forms of damage, such as cracking. A head made of iron goes for a little longer than that. If your engine has been running on the same cylinder head for more than five years, consider having it repaired or replaced.

  • Leaking Coolant- a coolant leak could indicate various problems, chief among them a cracked cylinder head. There are two major ways to detect leaking coolant. One of them is visually inspecting the head and cylinder block for spills. Another way is through the dashboard light. When coolant has been leaking, the cooling system is affected. Overheating then occurs, causing the “check engine temperature” light to come on.

  • Oil Leak- just like it happens with the coolant, a cracked cylinder head causes oil to leak. You may notice an oily spot on the ground when your car has been stationary for long. If the oil is spilling excessively, it will even trickle down the engine block visibly. Leaking oil may also cause the “check oil” icon on the dashboard to light up. Oil lubricates the inside parts of an engine. It also helps to dissipate heat. If it is leaking, it can mean reduced engine performance and even damage.

  • Smoke From Under the Hood- the cylinder head contains passages for the exhaust gases. It connects to the exhaust manifold and helps to vent out the products of combustion. In the worst of situations, cylinder head problems can involve severe cracking that allows exhaust gases to escape through the head. That would then appear as smoke coming from the engine area.

  • Reduced Engine Performances- the cylinder head houses most of the engine’s mechanical components. It also holds in the pressure of expanding combustion gases. When it cracks, these passages are affected. A lot more happens too, such as loss of seal. As you can guess, the engine will not run as required. The combustion becomes inefficient and engine strokes weak. Overall, the engine performance reduces.

  • Engine Misfires- a misfiring engine is directly related to the problem that we have just discussed. Cracks on the cylinder head cause pressure issues in the combustion chamber. If a stroke is not weak, it is not happening at all. Your car may miss strokes due to other problems, of course, but a cracked cylinder head is one of them. The partly burned fuel-air mixture could cause parts to gum up in addition to increasing emissions.

A cracked head does not necessarily need to be changed. It can be repaired easily, and at your local automobile repair shop. Smalls cracks are taken care of using a process called pinning. Larger cracks can be fixed by welding if the head is made from aluminum. Severe cracks on iron cylinder heads are repaired using furnace welding or the flame spray method.

Warped Cylinder Head Symptoms

2. Warped Cylinder Head Symptoms

Just like cracking, overheating is a major cause of a warped cylinder head. Some warping problems are the result of the mistakes of car owners. Many people falsely think that pouring water into the radiador can help cool the engine faster. But that only causes a rapid temperature fluctuation, leading to a warped or even cracked head.

To tell if a cylinder head is warped, check the area between the head and the gasket. The two parts should be flush. If they are not, you have a warped head. Alternatively, you can check the straightness of the head using a square. It is an easy procedure that also gives relatively accurate results. A warped cylinder head is usually repaired by machining. The process removes the raised parts to produce an even surface. This can be done at most vehicle repair facilities.

3. Porous Cylinder Head Symptoms

Gases or contaminants during casting can cause a cylinder head to become porous. The contaminants create voids. These voids may open to the outside of the cylinder head. However, resurfacing the head can reveal them.

When voids and holes become exposed, they may leak coolant or oil. Bad cylinder head symptoms could then begin to appear. Porous cylinder head symptoms include low levels of coolant, contaminated oil that appears milky, and overheating of the head and engine block.

Just like cracks, exposed voids can be fixed. Porous cylinder head repair involves filling the holes with a sealing material. And if they are too large, you may decide to replace the cylinder head. Aluminum heads are more prone to porosity than those made from iron.

cylinder head gasket problems

4. Cylinder Head Gasket Problems

The functions of the cylinder head gasket match that of the cylinder head: heat transfer, taking in compression pressure of the expanding gases, and more. When the gasket blows, the signs that appear are closely related to those shown by a failing cylinder head.

What causes a blown head gasket? The problem often occurs when the engine block and the head expand unequally, creating a gap between them. If the engine block and cylinder head feature different materials, the likelihood of gasket issues increases.

A damaged cylinder head gasket can also result from poor workmanship where seam does not provide a strong seal. Blown cylinder head symptoms are many and varied. They include:

  • External leaks- a blown head gasket causes coolant and oil to spill out of the head. A head gasket leaking oil externally may not be a big problem at first. However, it cause engine problems over time or if the leaking intensifies. Excessive loss of coolant will also become a major issue in the long run.

  • Sobrecalentamiento- a broken gasket head causes coolant and oil to leak. The two fluids cool the engine, and their loss can lead to overheating. If the coolant leaks into the cylinders, it gets heated and turns into steam. Apart from raising engine temperature, the steam may damage the catalytic converter and lead to costly repairs.

  • White or blue smoke- one of the most significant head gasket leak symptoms is white smoke coming out of the exhaust pipe. The smoke will also have a distinct sweet smell. The problem results from coolant and antifreeze mixture leaking into the combustion chamber. If it is oil that has leaked, the smoke is bluish.

  • Loss of engine power- a blown cylinder head gasket causes coolant and oil leaks. It also allows the air/fuel mixture to escape, leading to loss of compression in the cylinders. These cylinder head gasket problems affect the engine in one way or another and lead to reduced power. Your car then struggles to climb hills. During acceleration, the loss of power becomes even more apparent.

  • Contaminated oil- when coolant leaks out, it finds its way into the oil passageways and reservoir. When that happens, the oil becomes milky and loses its lubricating properties. That is one of the reasons why a dipstick can be used as a blown gasket head test. Just observe the appearance of the oil, and you will instantly tell if coolant has mixed with oil- most probably due to a blown gasket head sealer seam.

Can you drive with a blown head gasket? Well, you can, but only if you are ready to foot hefty engine repair costs. As we have seen, one of the signs that the gasket is blown is an overheating engine. Driving with such a gasket can, therefore, mean damage to cylinder block components.

A bad head gasket can be fixed, and easily. Compared to the cost to take care of damaged engine parts, cylinder head gasket repair is way cheaper. Alternatively, you choose to replace the damaged part. The cylinder head gasket price is still lower than the amount to fix a damaged engine, which is all the more reason to opt for repair.

9 Cylinder Head Tips to Prevent Damage

Cylinder Head Image

Keeping the cylinder head on good condition is easier than having it repaired or replaced- and less expensive. Follow these tips to ensure that.

1. Maintain your engine to prevent overheating instances. High temperature levels and fluctuations are major causes of cracked cylinder heads, warping, and other forms of damage.

2. If your engine overheats, avoid driving on. The best thing to do is pull up, switch off the engine, and wait for it to cool.

3. Avoid pouring water directly into the car radiator while hot to either cool or fill it up. The resulting contraction and thermal stress can cause the cylinder head to crack or warp. Wait until it cools completely then add water.

4. Always ensure the radiator is working properly, filled, and its cap is tightly sealed. A failed radiator can cause dangerous overheating and a cracked or warped cylinder head.

5. Ensure the engine thermostat is working correctly at all times. The fan too, and the belts. Leaking hoses should also be fixed.

6. Have the cylinder head inspected regularly and cracks repaired. If there are warped parts, have them machined. Severe damage can mean higher cylinder head repair costs.

7. Use the right bolts to secure the cylinder head to the engine block. It creates a tight seal and prevents the problems associated with loose seams, such as leaks.

8. Always ensure the cylinder head gasket is also in good condition. A broken gasket can lead to cylinder head and engine problems. Care tips include avoiding high temperature levels and fixing mild forms of damage.

9. If the cylinder head is too old, say 5 years or more, have it changed.


Cylinder heads do not last forever. They can also get damaged. Because a bad cylinder head affects engine performance, care should be taken to prevent failure. The cylinder head symptoms described here should help detect damage before it becomes severe. Doing so would save your car’s engine and help you avoid expensive repairs. To prevent unnecessary damage, make use of the head maintenance tips described here.

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