Cracked Cylinder Head – 8 Symptoms, Test & Replacement Cost!

Written By: Hira
Category: Uncategorized

A cracked cylinder head is a significant problem that car owners may face, affecting their vehicle’s performance and longevity.

This guide will walk you through the symptoms of a cracked cylinder head, how to test for this issue and an estimation of repair costs for such a condition.

Cracked Cylinder Head – An Overview!

A cracked cylinder head is a serious issue that can occur in any internal combustion engine.

This crucial component forms part of the combustion chamber and houses the engine’s valves and spark plugs.

When a cylinder head cracks, it can lead to several problems, including coolant leaks, reduced engine performance, and overheating.

Identifying a cracked cylinder head early on is vital to prevent further damage.

Symptoms might include unusual engine misfires, excessive exhaust smoke, and a significant loss of coolant with no visible leaks.

Testing for a cracked head often involves a compression test or a leak-down test, and in some severe cases, a visual inspection may be necessary.

Repair costs can vary based on the damage extent and the vehicle’s make and model. However, they can often be high due to the labor-intensive nature of the repair process.

8 Symptoms Of Cracked Cylinder Head

A cracked cylinder head can greatly harm the performance and safety of your vehicle.

Identifying the symptoms of this issue is crucial to seek timely repair and avoid further damage. Here are the nine major symptoms to look out for:

1. Excessive Exhaust Smoke:

A significant increase in the smoke emitted by the exhaust can be a telltale sign of a cracked cylinder head.

Cracked Cylinder Head - Symptoms, Tests & Replacement Cost!

This occurs when the integrity of the cylinder head is compromised, allowing oil, coolant, or fuel to mix with the combustion process.

Consequently, the color of the smoke can differ: black when oil is burning off, blue when coolant is involved, or white when fuel is burning off in the cylinders.

It’s important to address this issue promptly, as it can lead to further engine damage if left unresolved.

2. Engine Overheating:

Coolant may leak into the combustion chambers if the cylinder head is cracked or escapes from the engine.

This can result in the engine overheating, leading to potential damage and decreased performance.

Engine Overheating

It is crucial to promptly address cylinder head cracks to prevent further complications and ensure optimal engine functioning.

3. Decreased Fuel Efficiency:

If your vehicle suddenly starts consuming more fuel, it may be due to a crack in the cylinder head, causing a loss of compression.

This loss of compression can decrease the engine’s efficiency, resulting in increased fuel consumption.

It is important to address this issue promptly to prevent further damage and ensure the optimal performance of your vehicle.

4. Coolant Leaks:

Coolant may leak externally from below the exhaust manifold, easily detected by signs of coolant pooling or dripping.

Alternatively, internal coolant leaks may occur if the cylinder head is cracked, leading to coolant seeping into the combustion chambers.

It is crucial to address these issues promptly to prevent further damage to the engine and maintain its optimal performance.

5. Bubbles In The Radiator Or Coolant Overflow Tank:

If your cylinder head is cracked, it can lead to a significant issue where combustion gases can potentially escape into the cooling system.

This can result in the formation of bubbles, noticeable either in your radiator or coolant overflow tank.

It’s essential to address this problem promptly to prevent further damage and ensure the proper functioning of your vehicle’s cooling system.

6. Discolored Spark Plugs:

A cracked cylinder head, a common engine problem, can have serious consequences. When a cylinder head is cracked, it can cause coolant to leak into the combustion chambers.

This coolant leakage can contaminate the spark plugs, leading to performance issues and potential engine damage.

Cracked Cylinder Head

One visible indication of this issue is the presence of a white or rust-colored residue on the spark plugs.

It’s crucial to address this problem promptly to prevent further damage and ensure the smooth operation of your engine.

7. Engine Misfires:

If the engine starts to misfire, it could be a symptom of a cracked cylinder head.

This occurs when there is a loss of compression or when the spark plugs become contaminated with coolant or oil.

A cracked cylinder head can lead to inefficient combustion, reduced engine performance, and potential damage to other engine components.

It is important to address this issue promptly to prevent further complications and ensure the smooth operation of your vehicle.

8. Oil Contamination:

If coolant leaks into the engine oil through a crack in the cylinder head, it can cause the oil to become milky or frothy, which indicates a serious engine problem.

This issue arises when the coolant mixes with the oil, compromising its lubricating properties and potentially damaging engines.

It is crucial to address this situation promptly to prevent further complications and costly repairs.

How To Test Cracked Cylinder Head?

Knowing the symptoms of a cracked cylinder head is essential, but how can you definitively confirm it?

Fortunately, several tests can be done to check the integrity of the cylinder head and determine if it’s cracked.

Below, we provide a step-by-step guide on how to test a cracked cylinder head, empowering you to diagnose and address this potentially serious engine problem.

Remember, timely detection and resolution can save you from costly repairs and prolong your engine’s lifespan.

1. Visual Inspection:

One of the easiest ways to test for a cracked cylinder head is to inspect it visually.

You must remove any components obstructing your view of the head, such as the valve cover. Look for any fractures or breaks that may indicate a crack.

2. Coolant Leaks:

Check for internal or external leaks of the coolant. This can be done by checking the ground under your car for coolant puddles.

Also, check the coolant level in the reservoir – if it’s decreasing rapidly, it is a sign of a possible leak.

3. Compression Test:

Conducting a compression test is a valuable method for evaluating the overall health of an engine.

Compression Test

This test specifically measures the pressure in the cylinders during the compression stroke. In the event of low-pressure readings, it could indicate a cracked cylinder head.

4. Leak-Down Test:

Here’s an alternative way to assess the integrity of your cylinders.

By conducting a leak-down test, you can effectively detect any cracks that may not be easily identifiable through a compression test alone.

This comprehensive approach ensures a thorough evaluation of your cylinders’ condition, providing valuable insights for maintenance and repair.

5. Pressure Testing:

Conducting a pressure test on the cooling system can also unveil the presence of a crack in the cylinder head.

This test applies pressure to the cooling system, allowing you to identify leaks that may not be apparent to the naked eye.

6. Check For Contaminated Oil:

To properly inspect the condition of the oil, check for any signs of it appearing milky or frothy.

These indications may suggest a potential coolant leakage into the oil, which could be attributed to a cracked cylinder head.

Paying attention to these details is crucial as they can help identify and address any possible issues with the engine.

7. Check The Spark Plugs:

Inspect the spark plugs for any signs of discoloration. If you observe a white or rust-colored appearance, it could indicate coolant contamination.

This, consequently, indicates a potential issue with a fractured cylinder head.

Replacement Cost Of Cracked Cylinder Head

When replacing a cracked cylinder head, costs can vary greatly depending on your vehicle’s make and model, the damage’s extent, and where you live.

Here’s a table summarizing the replacement cost of a cracked cylinder head:

Component/ExpenseCost Range
Cylinder Head (Bare)$300 – $500
Complete Cylinder Head$600 – $750
Head Gasket, Bolts, Seals$50 – $150
Labor$400 – $800 (approx.)
Miscellaneous Items (Coolant, Oil, etc.)$30 – $50
Total Replacement Cost$780 – $1,550

The cylinder head can range anywhere from $300 – $500 for a bare cylinder head or up to $600 – $750 for a complete cylinder head with cams.

However, this does not include other components that may need to be replaced, such as the head gasket, bolts, and seals, which can add $50 – $150 to the cost.

Labor is another high cost. Replacing a cylinder head is complex and time-consuming, often involving several hours of work.

Most auto repair shops charge anywhere from $50 – $100 per hour for labor.

So, if a cylinder head replacement takes around 8 hours, you could be looking at an additional $400 – $800 just for the labor cost.

Lastly, don’t forget to include the cost of miscellaneous items such as coolant and oil, which could add another $30 – $50 to the final price.

In conclusion, replacing a cracked cylinder head can range from $780 to $1,550. Getting a detailed quote from a mechanic is essential to understand all the costs involved.


A cracked cylinder head is a significant automotive issue that, if left unchecked, can lead to serious engine damage.

The principal symptoms to be vigilant for are: excessive smoke from the exhaust, coolant leaking, declined engine power, and discolored spark plugs.

You can perform a basic inspection using the abovementioned techniques to check for a cracked cylinder head.

However, it is always recommended to consult a professional mechanic for a definitive diagnosis.

The repair cost for such a problem can vary greatly, hinging on factors such as the vehicle’s make and model, the extent of the damage, and labor costs.

Generally, you can anticipate costs ranging from $780 to over $1,550.

Always ensure you get a detailed quote from your mechanic to understand all the costs and make an informed decision.

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