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Can a Cracked Cylinder Head Be Fixed? Your Options for Repair vs. Replacement

Has your mechanic told you your truck has a cracked cylinder head? Or perhaps a buddy heard you talking about some problems with the vehicle and offered that up as a possible diagnosis?

Read on to learn exactly what a cracked cylinder head means and what your choices may be for fixing it. A cracked cylinder head used to spell disaster for Nanaimo drivers, especially small business owners and fleet managers. But the good news is that state-of-the-art automotive technology today gives you more options than in previous times, including cleaning and resurfacing of cylinder heads, as well as rebuilding and replacement.

What Is a Cracked Cylinder Head?

A cylinder is an essential element of a vehicle engine. In that chamber, combustion takes place, which releases energy to power the truck or car. The cylinder head seals the cylinder inside the engine block.

Most smaller and non-performance vehicles have one or two cylinder heads, and some cylinder heads may seal multiple cylinders. Larger diesel engines, however, can have more cylinder heads, depending on the number of cylinders and the engine configuration.

A cracked cylinder head means the integrity of that seal has been compromised. This allows unwanted leaks from the combustion chamber.

Common Causes of a Cracked Cylinder Head

There are a number of things that can cause a cracked cylinder head, including:

  • Engine overheating, stressing metal parts

  • Failed thermostat, which can result in the vehicle running too cold, causing wear

  • Faulty water pump, resulting in improper coolant circulation and overheating

  • Air present in the cooling system, which creates hot spots

  • Leaking coolant, usually resulting from engine overheating

As you can see, many of these causes overlap with each other, which is why addressing any one of these immediately is vital to the health of your engine.

What Are the Signs of a Cracked Cylinder Head?

What are the telltale signs of a cracked cylinder head? Watch out for these symptoms:

  • White smoke coming from the exhaust, which usually indicates coolant is entering the combustion chamber (you may also see leaking coolant)

  • Engine overheating due to coolant loss

  • Bubbles in the coolant from the presence of combustion gasses

  • Strong odour coming from the engine, such as a sweet smell from coolant burning

  • Visibly leaking oil, confirmed by low oil levels and a low oil pressure light on the instrument panel

  • Poor engine responsiveness and loss of power, including misfire or the feeling of the engine “slipping”

These problems usually get worse over time.

How do you know if you have a cracked cylinder head vs. engine block compromise? And how can you tell if you have a cracked cylinder head or blown gasket, which sits between the cylinder and the head?

You may not be able to. These engine concerns all tend to have similar signs. In fact, you could have more than one of these problems occurring simultaneously.

That’s why it’s so important to see a mechanic right away, both to sort out a diagnosis and to prevent the problem from getting worse and causing more damage. A mechanic that specializes in engines and engine machining is your best bet, as they have the experience and equipment to run pressure, vacuum, and Magnaflux tests to identify even the smallest of leaks and do any needed repairs.

Can a Cracked Cylinder Head Be Fixed?

In many cases, a cracked cylinder head can be repaired rather than replaced, depending on the location and extent of the damage. This is beneficial, as it’s generally more expensive to replace a cylinder head than to repair one. The cost of both repair and replacement is determined by factors like:

  • Age, make, and model of the vehicle

  • Availability of engine parts

  • Engine configuration and labour involved

  • Head material (aluminum vs. iron or alloys like steel)

  • Extent of the head damage

  • Number of heads needing repair/replacement

  • Damage to other engine parts, like the cylinder itself

There are a couple of options available to British Columbia residents as an alternative to replacing a cracked cylinder head with a new part.

First, there are remanufactured cylinder heads, which are a less expensive option than installing a replacement head. These are cylinder heads that have been rebuilt with other parts, using recasting and machining to create something that works like a new head. Remanufactured cylinder heads are stress-tested to ensure they can handle the pressure when they are placed in the engine.

In other instances, a cracked cylinder head can be welded back together and resurfaced with a Rottler CNC surfacer, which creates a perfect fit with the head gasket. The tight fit is essential to the cylinder head’s function going forward. In particular, multi-layer steel (MLS) head gaskets in newer vehicles today require this super fine finish.

The best engine machining shops provide related services, such as:

  • Stainless steel O-ringing to add further sealing to the head gasket

  • Sleeving to repair worn or damaged cylinders

  • Hot tank and industrial jet or sonic cylinder head cleaning for proper function

Diagnosing and repairing or replacing a cylinder head is never a job you should attempt on your own. When you go to a highly rated professional, you know the job will be done right, which protects your investment in your personal vehicle or a vehicle you have purchased for your business.

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