A blown head gasket can spell huge trouble for your vehicle along with big repair bills. But, do you know what causes a head gasket to fail and symptoms to be on the lookout for? If you suspect you might have a head gasket that’s seen better days, then keep reading! We’ll provide all the information you need to know about what a head gasket does and what you might experience if yours fail. Plus – we’ll detail what it takes to have your head gasket repaired so that you can get back on the road again, and how hard you can expect it to hit your wallet. Let’s dive in!

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What Is a Head Gasket?

Your head gasket serves many purposes and is a critical part of your car’s engine. The first is acting as a “gatekeeper” of sorts in directing fluids where they need to go. It provides a tight seal and keeps your engine oil and coolant from mixing as they both flow through the passages between your engine block and cylinder heads. The head gasket seals the block to the heads.

Without a proper seal, these fluids would mix with each other, and the result would not be good! This seal allows your cooling system to function properly, thus preventing your car from overheating. It also allows the oil to circulate as it should, thus providing critical lubrication to your internal engine parts.

In addition, the seal provided by your head gasket allows compression to build inside the cylinders of your engine. Without this seal, your engine would lose compression and would not perform well. With a total loss of compression, the engine would not even run at all! Hence, you can see why your head gasket is so important!

Head gaskets come in a variety of materials. Each has pros and cons, although some are better suited for specific applications than others. Here are some of the most common head gasket materials:

  • Composite

Composite gaskets are rarely used in modern applications because they do not hold up well under high temperatures. They also routinely contain asbestos. They do conform to surface well and provide a great seal, but they become hard and brittle in a short period of time. You can sometimes find these on older cars, but will rarely run across a composite head gasket on modern vehicles.

  • Copper

Copper gaskets are typically used in high performance applications. Copper is great at distributing heat, and it helps prevent overheating and distortion in high performance applications. It is also a soft metal, so it provides a good seal between the block and heads. Copper tends to be quite expensive, so expect to pay a little more for a copper gasket.

  • Multi-Layered Steel

Multi-layered steel gaskets are most common on modern vehicles, and they provide great all around performance. They consist of several thin layers of steel that are joined together with a composite material. These types of gaskets provide the durability of a metal gasket with the malleability of a composite gasket. They are a little more expensive than traditional composite gaskets, but they last much longer and provide a stronger seal.

Now you should have a good understanding of what a head gasket is and what purpose it serves. So, let’s begin to take a look at what might cause a head gasket to fail.


What Causes a Blown Head Gasket?

Although head gaskets can fail for several reasons, there are things you can do to help prevent them from failing. They are designed to last for many years and thousands of miles, so you might own a car for years and never have to worry about head gasket issues. Here are some of the most common culprits of head gasket failure:

  • Overheating

Heat is a head gasket’s worst enemy. Each time you drive your car, your head gasket is subjected to extremely high temperatures. Thankfully, the gasket is made to withstand these temperatures, as long as they are within the normal operating range. If temperatures go above this range, this is where trouble begins.

If your car overheats, then your head gasket is put through additional stress. These hotter than normal temperatures can cause the melting or warping of the gasket in ways that it should not. This can be detrimental to the seal provided by the gasket and can cause a head gasket leak to develop.

This is why it is so critical to ensure that your engine coolant level stays in the proper range, and that your entire cooling system including your water pump and other components are functioning properly. Preventing engine overheating goes a long way to extending the life of your car’s head gasket.

  • High Pressure

Pressure inside the cylinders of your engine and combustion chambers is necessary to move the pistons back and forth as your engine runs. Your car has a default compression ratio that details exactly how much pressure should exist there. However, some car owners like to add aftermarket accessories such as turbochargers or superchargers that increase this pressure. By increasing this pressure, more air and fuel can be put into the cylinders causing increased performance.

However, with this increased performance comes a downside. Your stock head gasket is not made to handle the extra pressure caused by these external devices. Increasing the pressure inside your engine can cause a blown head gasket very quickly, and this type of failure is often abrupt and catastrophic.

If you feel the need to increase your engine’s performance through the use of a supercharger or similar device, make sure that you upgrade your head gasket as well. Many aftermarket head gaskets are made to withstand this added pressure, and they will hold up to the extra stress put on your engine. Just be sure to properly match the head gasket with the amount of pressure that will be present inside the cylinders.

  • Age

As with most parts on your car, head gaskets can fail simply due to age. The constant wear and tear that your head gasket experiences causes them to become hard and brittle over time. Even under normal conditions, a head gasket will eventually fail due to its age.

While eventual failure will happen, you can rest easy knowing that it should be years down the road. Modern head gaskets are designed to last for many years, and it is not uncommon for a head gasket to last 20 years or more on a well-maintained vehicle. So, keep your vehicle in good shape and perform regular maintenance, and you should not have to worry about replacing a head gasket any time soon.

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Signs of a Blown Head Gasket

If you’ve read this far, you might be wondering how to tell if you have a blown head gasket. If you suspect that you might have a bad head gasket, there are some telltale signs that you can look for to determine whether that is the likely problem. Here are some of the most common blown head gasket signs:

  • Coolant Leaks

As we mentioned previously, your head gasket creates a seal that allows coolant and oil to flow through your engine without leaking. If you begin to notice drops of coolant underneath your car, you need to do some additional digging to determine the source. It could be from a head gasket failure that needs to be repaired before additional damage is done. An oil leak might also be a sign of a head gasket problem, but oil can leak from many different places, so additional diagnosis would need to be completed.

  • Mixing of Fluids

This is almost always a surefire one of the symptoms of a blown head gasket. As your engine and coolant circulate through the engine, they remain in separate passageways. These two fluids should never be mixed as neither can perform its job properly if they do. If you notice a mixing of these fluids, then it almost always means that the seal is broken and your head gasket is blown. The coolant passages are no longer sealed from the oil passages, and the two fluids mix with each other as they circulate.

You can check your oil dipstick or remove the oil cap and see whether the oil appears milky and frothy. This probably means that coolant has gotten mixed into it. Also, check your overflow tank for dark or murky antifreeze. You can pop your radiator cap and take a look inside as well, but make sure the car is cool before doing this. 

  • White Smoke from Tailpipe

If you notice white smoke coming from the tailpipe, especially if it has a sweet smell to it, then you will probably need a head gasket replacement soon. When the head gasket no longer seals properly, coolant can seep into the engine’s cylinders. As the engine runs, this coolant burns off and gets sent out with the exhaust gases through the exhaust pipe. The coolant produces a white smoke as it vaporizes, so you will notice this coming from your exhaust.

  • Overheating

When a leak develops in your cooling system, then overheating becomes a problem. A lack of circulation through the heads of your engine can cause your car to overheat, and a blown head gasket might be the culprit. So, keep your eye on your temperature gauge to make sure that it stays in the normal range. Even if a head gasket is not the problem, if you continue to run your car too hot, then your head gasket will not survive much longer. Overheating could also be a sign of a bad thermostat or leaking radiator hose, but you should make sure to fix any of these items immediately. If left unattended, you might be looking at a cracked head and very expensive repairs in the future.

  • Loss of Compression

When the head gasket loses its seal around your cylinders, then your car will lose compression. You might notice a lack of performance from your engine or hard starts when you attempt to crank your car. If the loss of compression is bad enough, your car might not run at all. 

  • Misfires or Fouled Spark Plugs

When coolant or oil enters your cylinders, it can wreak havoc on your spark plugs. These liquids being present can cause your plugs not to fire properly, and they will eventually foul out. This means that the plugs will no longer produce the spark necessary to complete the combustion process inside the cylinder. You might notice your car running a little rough or missing occasionally. If you plugs start to foul out, then this could be a sign that your head gasket has developed a leak.

  • Check Engine Light

Most modern engines will illuminate the check engine light when they sense a misfire or other problems. If your light is on, then you should have it checked right away to determine the cause. Most auto parts stores will read the code for you at no charge to help diagnose the problem. This could signal a number of potential issues, but reading the code should help narrow down what caused the light to come on.


How to Fix a Blown Head Gasket Without Replacing It

Fixing a head gasket might seem like a complex process, so you might be wondering if it’s possible to fix the gasket without actually replacing it. In some cases, you can fix the gasket without replacing it. If you can catch the problem early enough before it gets too bad, then it can be a simple fix.

Commercial automotive sealants are available that can repair a head gasket without tearing anything apart in your engine. Simply remove your radiator cap and pour the sealant into your radiator. Start your engine and allow the sealant to circulate through the system.

As it encounters the leak, the head gasket sealer will do its job and seal the leak back off again. To reiterate, this only works on small leaks and will not re-seal completely blown head gaskets. However, if you have a small problem, it’s definitely worth a shot before spending tons of money on a huge repair.


What Does a Blown Head Gasket Repair Cost

The cost to repair a blown head gasket varies depending on the amount of work that needs to be done. If a sealant will do the job, then you’ll only be out $20 or so. However, if the gasket needs replacing, you can expect to pay much more than that.

The cost of the gasket itself is not that much. Most head gaskets cost anywhere from $40 to $150 depending on the make and model of your car. The real money comes in from the labor costs. Replacing a head gasket is a complex task that requires many hours of work from an experienced mechanic.

With mechanics charging anywhere from $75 to $150 per hour, you can expect to pay $500 to $2,000 to have the head gasket replaced. That’s no small sum of money! If you have an older vehicle with additional problems, it might not be worth sinking that amount of money into the car. In that case, you might be better off selling your car to Auto Wranglers. We buy cars in any condition throughout the country, and we’ll buy yours too.

We’ll make you an instant cash offer to purchase the vehicle, and we always provide free towing and pickup. Instead of spending thousands of dollars on a repair, just sell us your car so that you can use the money to buy a new one. That will take the worry and headache of that old clunker away!



The head gasket on your car serves a very important purpose, and when it blows, it can cause major issues for your engine. Thankfully, they last for many years under normal wear and tear, so you shouldn’t have to worry about replacement for quite a while. If you do experience problems, you might be able to get by with a quick and easy repair if you catch it before it gets too bad.

Once things get bad, they get really bad. Replacing the head gasket is a time-consuming and expensive repair. If you don’t have a thousand or so dollars sitting around for it, then you should consider selling your car to Auto Wranglers. Our process is fast and easy, and we’ll have cash in your pocket quickly. You can use this extra money to buy yourself a new car instead of sinking tons of cash into that old car of yours.

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