How to Replace a Head Gasket

In every combustion engine, the cylinder head must be mated to the engine block for it not only to operate but to keep substances contained. The component that’s used to seal the two parts together is called a cylinder head gasket, or more commonly, just a head gasket. And when this seal fails, it can cause a variety of symptoms that require a swift and long-lasting repair.

Head gasket replacement is a significant job, and it can cost into the thousands of dollars to complete at a garage. If you’re doing the job yourself, you can save bundles of cash, but it’s crucial to get the job done right. Here’s what you need to know about the head gasket’s purpose, symptoms you can encounter, and general steps to replace it.

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Introduction to Head Gaskets

A head gasket provides a seal between the engine block and the cylinder head. It ensures that the combustion process remains contained within the cylinders while allowing coolant and oil to flow through the engine without mixing.

The most common type of head gasket is a multi-layered steel gasket that has between two and five thin layers sandwiched between the upper and lower surface. Other types can be fiber-based or even copper coated. Along with a durable ring around the cylinder, it seals the engine oil and coolant passages with materials like silicone. And while you might not expect this gasket to ever fail, it can and does.

Signs of a Faulty Head Gasket

When a head gasket fails, there are going to be definite symptoms, especially as time progresses. They an include:

• Overheating engine
• White smoke from the exhaust
• Loss of coolant with no visible leaks
• Milky oil appearance
• Bubbles in the radiator

One or more of these symptoms should trigger you to immediately inspect the head gasket and figure out the appropriate parts and processes to get it fixed.

Preparing for the Replacement

To change the head gasket is a complicated process that requires diligent cleaning and precise assembly. To get the job done right, you’ll need tools and materials like:

• Wrench set
• Torque wrench
• Screwdrivers
• Pliers
• Gasket scraper
• Industrial cleaning products
• New head gasket
• New head bolts
• Engine oil and coolant
• Straightedge for checking surface flatness

When you take on the job of head gasket replacement, there are inherent dangers and challenges to be aware of. Always work in a well-ventilated area, and wear safety gloves and glasses. Disconnect the battery before starting any work, and use jack stands to support the vehicle securely if lifting is required.

Removing the Old Head Gasket

The first step is disassembly. When removing parts and fasteners, mark where each goes to help with reassembling your vehicle afterwards.

1. Drain coolant. Place a drain pan under the radiator and open the drain valve. Allow all the coolant to drain into the pan.

1. Drain oil. Position another drain pan under the oil pan and remove the drain plug. Let the oil drain completely.

1. Remove intake and exhaust manifolds. Using the wrench set, remove the bolts securing the intake and exhaust manifolds.

1. Remove valve cover and camshaft. Carefully remove the valve cover, followed by the camshaft if necessary.

1. Remove cylinder head bolts. Loosen the cylinder head bolts in the correct sequence as specified in your service manual. Remove the cylinder head and place it on a clean surface.

1. Remove the bad head gasket. Peel the old head gasket material off of the upper and lower end, inspecting for any irregularities and points of failure.

Installing the New Head Gasket

A new head gasket can be susceptible to failure if the surfaces aren’t clean and straight, so don’t skip over or rush through the preparatory phase.

1. Clean surfaces. Use a gasket scraper and cleaning products like brake cleaner to remove any remaining gasket material, rust, or debris from the cylinder head and engine block surfaces. It needs to be flawless before installing the new gasket. Flush the cooling system to remove any oil contamination.

1. Check for unevenness. Place a straightedge over the cleaned surfaces and use the light-gap method to check for any unevenness or distortions. Any gaps visible through the straightedge indicate unevenness. If there’s more deviation than the manual specifies as an allowable tolerance, you may need to have the cylinder head machined flat before reassembly.

1. Position the new head gasket. Fit the new head gasket perfectly over each cylinder bore by lining up its features with the engine block. Press down evenly until it is seated in place. If the manual indicates that sealant is required on bolts or surfaces, ensure you use the correct type and amount.

1. Reinstall cylinder head. Place the cylinder head back onto the engine block and seat it onto the dowels, aligning it with the block.

1. Install new bolts. Install the new head bolts, tightening them evenly in the correct sequence. Use a torque wrench to ensure the bolts are tightened to the manufacturer’s specifications.

Post-Installation Checks and Testing

1. Reinstall engine parts and peripherals. Reattach the intake and exhaust manifolds, followed by any other parts you removed during the disassembly process.

1. Refill coolant and oil. Refill the engine with fresh coolant and oil.

1. Start the engine. Start the engine and let it run for a few minutes. Check for any leaks around the head gasket area.

1. Check engine performance. Take the vehicle for a short drive to ensure everything is functioning correctly. Watch for warning lights or other indicators that there might be an issue to fix.

Remember to follow each step carefully, prioritize safety, and consult your vehicle’s service manual for specific instructions. When you’re after the right parts and tools to get the job done right, AutoZone has what you need. Shop confidently online and in-store with trusted names like Duralast available.

FAQ/People Also Ask

Head gaskets can fail due to engine overheating, poor installation, or using the wrong type of gasket material.

Replacing a head gasket can take anywhere from 6 to 12 hours, depending on the vehicle and the level of expertise.

If you have experience with automotive repairs and the necessary tools, you can replace a head gasket yourself. However, if you’re unsure, it’s best to hire a professional to avoid potential mistakes that could result in further engine damage.

Common symptoms include engine overheating, white smoke from the exhaust, loss of coolant, milky oil, and bubbles in the radiator.

If you notice coolant leaking from your engine, address the issue immediately. Inspect the head gasket for signs of damage and consider replacing it if necessary.

Advice, how-to guides, and car care information featured on AutoZone.com and AutoZone Advice & How-To’s are presented as helpful resources for general maintenance and automotive repairs from a general perspective only and should be used at your own risk. Information is accurate and true to the best of AutoZone’s knowledge, however, there may be omissions, errors or mistakes.

Be sure to consult your owner’s manual, a repair guide, an AutoZoner at a store near you, or a licensed, professional mechanic for vehicle-specific repair information. Refer to the service manual for specific diagnostic, repair and tool information for your particular vehicle. Always chock your wheels prior to lifting a vehicle. Always disconnect the negative battery cable before servicing an electrical application on the vehicle to protect its electrical circuits in the event that a wire is accidentally pierced or grounded. Use caution when working with automotive batteries. Sulfuric acid is caustic and can burn clothing and skin or cause blindness. Always wear gloves and safety glasses and other personal protection equipment, and work in a well-ventilated area. Should electrolyte get on your body or clothing, neutralize it immediately with a solution of baking soda and water. Do not wear ties or loose clothing when working on your vehicle.

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