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Head Gasket Replacement 101: Signs + How to Do It

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Wondering if it’s easy to replace a cylinder head gasket?
Whether you plan to do it yourself or hire a mechanic, the answer is mostly no

Head gasket replacement can be an arduous process, and you may even find yourself asking if it’s worth it — depending on the damage and costs. 

But fret not! 
We’ll take you through the signs of a blown head gasket to help you catch the issue early and the steps to replace it. We’ll also cover potential head gasket repair costs so you can budget for the replacement in advance.

Let’s go.

This Article Contains:

8 Signs that Indicate You Need a Head Gasket Replacement

A bad head gasket will display symptoms like:

  1. Engine misfires or knocking: A blown head gasket can hamper combustion in an engine, leading to cylinder misfire, engine knocking, or pre-ignition (the air-fuel mix ignites before the timed spark).

  2. Power loss: Head gasket failure can decrease the pressure in the combustion chamber, resulting in a loss of power

  3. Leaking coolant: A blown head gasket seal may let coolant leak into the combustion chamber or oil passages of your engine, leading to cooling system failure.

  4. Engine overheating: Low coolant means your engine won’t be able to cool down as needed — resulting in overheating.

  5. White smoke from the exhaust pipe: Coolant leaking into the combustion chamber will burn, releasing white smoke and water vapor from the exhaust.

  6. Milky engine oil: If engine coolant gets into the oil passages, your engine oil will turn milky and accelerate engine wear.

  7. Fouled spark plugs: A blown gasket may allow coolant or oil into the cylinders, which can then foul a spark plug.

  8. Bubbles in the coolant reservoir: A bad head gasket could let combustion gases into the cooling system. This increases the pressure in the coolant reservoir, causing bubbles.

Now that you know the signs that point to a faulty head gasket, let’s see how to replace it.

How to Replace a Head Gasket (Step-By-Step)

A head gasket replacement can be a complex and expensive procedure. So, you should assess whether it’s worth getting a head gasket repair based on your car’s miles and overall condition.

For example, repairing a blown head gasket that has led to severe engine damage could cost more than the value of a vehicle. In such cases, it may be better to scrap your car than fix it. 

Moreover, the replacement can involve the removal of several engine parts. So, unless you’re sure of handling the job, it’s best to leave it to a professional mechanic

Here’s how a mechanic would do it:

  1. Check the service manual to identify specific procedures and tools required for your vehicle’s make and model.
  1. Disconnect the battery
  1. Drain the oil and coolant from your engine. 
  1. Remove the components connected to the cylinder head, including the exhaust manifold, valve cover, intake manifold, and drive belts. They’ll make a note to remember where each engine component goes once the replacement is done.
  1. If needed, they’ll remove the timing belt or chain. The mechanic will take note of its alignment before disassembling it.
  1. Remove the head bolts or fasteners in sequence before removing the cylinder head from the engine block. 
  1. Take out the faulty head gasket. 
  1. Clean the cylinder head surface to prevent dust or debris from coming into contact with your new gasket. They’ll also clean the bolt holes that help tighten the cylinder head to the engine block.
  1. Pressure test the cylinder head to check for cracks and resurface the head. If there are cracks, the mechanic will replace it or apply a gasket sealer (for minor cracks). 
  1. Inspect the new gasket surface for distortions or unevenness using the straightedge or light-gap method.
  1. Line the new head gasket perfectly over each cylinder bore before seating it. 
  1. Place the cylinder head back on the engine block.
  1. Screw in new head bolt pieces if the old ones must be replaced. They’ll apply the correct torque when fastening in a head bolt. 

Note: Using the correct torque specifications (as specified by the manufacturer) is necessary to prevent a head gasket leak (oil or coolant leak). 

But how important is this replacement?
Let’s find out.

Is a Head Gasket Replacement Urgent?

Yes, you should get a head gasket repair as soon as possible since it could involve a coolant or oil leak. Issues like engine overheating, pre-ignition, and cylinder misfire due to head gasket failure will cause critical damage to your engine, requiring engine repair. 

Moreover, if you run out of coolant while driving, you risk your engine catching fire. 

Next, let’s explore the potential head gasket repair cost.  

How Much Does a Head Gasket Replacement Cost?

Repairing a head gasket could set you back by $1,600 to $2,000. 

The replacement parts can cost between $60 to $1,250, depending on their quality and your vehicle’s make and model. However, the major expense is labor costs since the gasket repair process involves disassembling the engine, which can be time-consuming. 

Other factors that influence the head gasket repair cost include the severity of the problem and any additional engine component that needs replacement. This can include:

Still have a few doubts?
Keep scrolling as we address some additional queries.

3 FAQs about Head Gaskets

Here are answers to common questions about head gaskets: 

1. What Does a Cylinder Head Gasket Do?

Head gaskets seal the engine cylinders and combustion chamber, preventing coolant and oil from entering them when circulating through the engine.

It also helps maintain the compression pressure required for sustaining engine power. 

2. How Long Do Head Gaskets Last?

Whether in a Honda Motor Company or Ferrari car, manufacturers make head gaskets sturdy and durable to withstand high temperatures and pressures. So, they can last between 10 to 15 years, depending on their quality and your vehicle conditions. 

3. How Can You Prevent Head Gasket Issues?

Follow these tips to prevent head gasket failure:

  1. Maintain the recommended engine coolant levels to prevent overheating and damage to the head gasket.
  2. Replace engine oil regularly according to your owner’s manual recommendation to ensure your engine runs smoothly.
  3. Use the right fuel octane level to prevent pre-detonation and knocking.
  4. Avoid carrying heavy loads or excessive idling, which can overload your engine and stress the head gasket.
  5. Keep up with regular maintenance and address engine issues promptly to prevent a head gasket leak or damage.

Resolve Head Gasket Issues with AutoNation Mobile Service

Head gasket replacement can be a complicated and time-consuming process. You may also need additional engine repair due to head gasket leaks. So, it’s worth considering if you should get this expensive replacement done in the first place. 

But if you decide to do the replacement, it’s best to leave it to professionals like AutoNation Mobile Service.

We’re a mobile auto repair and maintenance solution that services most vehicles, from Honda Motor Company to Porsche cars. We also offer upfront pricing and a 12-month, 12,000-mile repair warranty

Contact us, and we’ll send expert technicians to resolve your auto repair needs right from your driveway.