Hey there, I’m Robby – a certified auto mechanic with over 20 years of wrench-spinning experience under my belt. I’ve seen just about every engine problem out there, including my fair share of cracked cylinder heads. Let me tell you, these sneaky cracks can cause huge headaches if you don’t catch them in time.
In this article, I’ll draw from my decades of hands-on knowledge to walk you through everything you need as a car owner to spot, diagnose, and fix a cracked cylinder head. I’ll cover what causes the cracks, the tell-tale signs to watch for, your repair options, and costs to expect. Whether you plan to DIY or hand it over to a pro, you’ll be armed with everything you need to know about Cracked Cylinder Head Repair Cost. Stick with me and you’ll be confidently addressing this frustrating issue, avoiding further damage, and saving your engine.
What is a Cylinder Head and What Does it Do?
The cylinder head is a crucial engine component that sits above the cylinders and contains the combustion chambers where fuel ignition takes place. Its main functions are to:
- Seal the tops of the cylinders and combustion chambers
- Hold the intake and exhaust valves that allow air/fuel mixture in and exhaust gases out
- Provide passages for coolant and oil to flow through
It is typically made of aluminum or cast iron and bolted to the engine’s cylinder block. The cylinder head works closely with the head gasket which seals the joint between the head and block.
Common Causes of a Cracked Cylinder Head
There are a few key reasons that can cause a cylinder head to crack:
The #1 cause of cracked heads is overheating. When the engine overheats, it creates excessive pressure and stress which can warp and crack the head. Common causes of overheating include low coolant, bad water pump, stuck thermostat, or coolant leaks.
Improper Head Bolt Torque
If the head bolts are over-tightened during installation, it can distort the head and cause cracks over time. Under-tightening can also lead to leaks and cracking. Proper torque specs must be followed.
Extreme Temperature Changes
Frequent extreme hot and cold cycles can cause the head to expand and contract, eventually leading to cracks from metal fatigue. This is most common in areas with extreme winters.
In rare cases, imperfections in the casting process can cause inherent weak spots leading to cracks down the road.
Signs and Symptoms of a Cracked Cylinder Head
Watch out for these common signs of a cracked cylinder head:
- Coolant or oil leaks – Visible leaks around the head gasket area indicate an external crack.
- Engine overheating – Cracks allow coolant to escape the system causing overheating issues.
- White smoke from exhaust – Coolant getting into the combustion chamber will burn and produce white smoke from the tailpipe.
- Low coolant levels – Coolant escaping through the cracks will rapidly lower levels.
- Rough idle, loss of power – Compression issues from cracks can cause misfiring and idle problems.
- Milky oil – Coolant getting into the oil through internal cracks turns the oil milky.
Cylinder Head Crack Repair Options and Costs
If you suspect a cracked cylinder head, a mechanic will need to fully inspect and diagnose it to determine the location and extent of cracking. From there, you generally have two options:
Cylinder Head Rebuild
For minor cracks in accessible areas, it may be possible to repair the head by welding, pinning or epoxy sealing of the cracks. The head is removed, cracks assessed, and repaired as needed. This avoids a full replacement but is still very labor intensive. Rebuild cost range: $1,000 – $2,500
Cylinder Head Replacement
In most cases of cracking, a full cylinder head replacement will be required. This involves removing the damaged head, installing a new or remanufactured replacement, and reassembly. Cylinder head replacement cost range: $1,500 – $4,000
Other factors like make/model of vehicle, parts cost, and labor rates can influence the final repair cost. Diagnostics should always be done first before determining if rebuilding or replacement is the better fix.
DIY Cracked Cylinder Head Repair?
While advanced mechanics may be able to rebuild or replace a cylinder head themselves, I strongly recommend having this type of repair done by a repair shop or mobile mechanic in your town. Cylinder heads are complex and critical components. Improper removal, installation or torque procedures can lead to further damage or engine failure.
The skills, tools and experience needed to properly assess cracks, machine valves and seats, check clearances and torque the head safely make this a job best left to expert technicians. DIY repairs often lead to comebacks or the need for a complete engine rebuild.
Preventing Cracked Heads
While cylinder heads will eventually wear out, you can help prevent premature cracking by:
- Maintaining proper coolant levels and changing it per your owner’s manual
- Fixing any leaks or overheating issues immediately
- Not over-revving the engine while cold
- Avoiding sudden cooling of hot engines
- Using only recommended coolants, not pure water
Regular maintenance and avoiding overheating are key to maximizing the life of your cylinder heads. But when cracks do occur, have a professional mechanic diagnose and repair it properly.
When to Ask a Mechanic
As you can see, dealing with a cracked cylinder head is not something to take lightly. The repairs can get complicated and expensive. If you notice any symptoms of a cracked head, the best course of action is to have your vehicle inspected by a professional mechanic.
The experts at Mechanic Answer are a great option for getting fast, affordable advice from certified mechanics online. You can get specific guidance tailored to your vehicle’s make and model. Plus, their average response time is under 20 minutes so you’ll get answers when you need them.
Diagnosing and repairing a cracked cylinder head is crucial for the performance and longevity of your engine. By knowing the warning signs, costs, and preventive care, you can address this issue promptly if it arises and get back on the road. With the right mechanical knowledge and services, a cracked head doesn’t have to lead to an engine replacement.
A cracked cylinder head is a serious issue that requires immediate attention to prevent further damage. Knowing how to identify symptoms like overheating or oil leaks can help catch cracks early. While minor cracks may be repairable through rebuilding, most cases require a full cylinder head replacement by a professional mechanic. With costs ranging from $1,000-$4,000, cracked heads are an expensive fix, but far less than a full engine rebuild. Stay diligent on maintenance and cooling system health to help avoid cracked heads in the first place. But when problems do arise, use the guidance in this article to get your car repaired and running smoothly again.
Cracked Cylinder Head Repair Cost Frequently Asked Questions
Is a cracked cylinder head repairable?
Yes, a cracked cylinder head can often be repaired. The repair technician will inspect the damage and determine if the cracks are small enough to be welded closed. For larger cracks, they may need to disassemble the cylinder head and have it professionally machined and rebuilt with new valves and seats. As long as the cracks have not caused severe damage, most cracked heads can be repaired and put back into service.
Can you drive with a cracked cylinder head?
It is not recommended to drive with a cracked cylinder head. A small crack may allow coolant to leak into the combustion chamber or oil to leak externally. This can cause overheating issues, oil contamination, and even hydrolock (where coolant fills the cylinder). Driving with a cracked head risks further damaging the engine to the point where complete cylinder head replacement is needed. Have your vehicle towed to a repair shop to diagnose and fix the issue.
What causes a cracked cylinder head?
Some of the most common causes of a cracked cylinder head are:
Overheating - This can warp and crack the head. Coolant boiling over is a sign of this.
Improperly torqued head bolts - Bolts that are too loose or too tight can put stress on the head and cause cracks.
Defective head gasket - This allows coolant and combustion gases to reach the head, leading to cracking.
Excessive thermal cycles - Repeated heating and cooling cycles weaken the head over time.
Physical damage - External impacts from debris or accidents can crack the head.
What are the symptoms of a cracked cylinder head?
Coolant leaks - Visible leaks of coolant from the head gasket surface.
Overheating - Engine temperature rises rapidly due to coolant loss.
White exhaust smoke - Coolant burning in the combustion chamber causes white smoke from the tailpipe.
Oil contamination - Coolant making its way into the oil through the crack.
Loss of compression - Compression leaks from the combustion chamber due to the crack.
Rough idle - Engine may misfire or idle roughly with a cracked head.
How long will an engine last with a cracked head?
An engine with a cracked cylinder head will usually fail within a few hundred miles if driven under normal conditions. The excessive heat and pressures inside the combustion chamber will cause the crack to rapidly spread. Once coolant starts leaking out or into the oil, severe internal engine damage occurs quickly. To prevent complete engine failure, have the vehicle serviced and the head repaired or replaced as soon as cracked head symptoms appear.