Blown Head Gasket Symptoms

A head gasket removed from a vehicle

A car's engine is divided into two sections: the engine block, which houses the pistons and cylinders, and the cylinder head, which contains the valves, spark plugs, and other components. The head gasket can be found between these two sections. A blown head gasket can make your vehicle dangerous to operate. Check out some blown head gasket symptoms here.

What Are The Symptoms of a Blown Head Gasket?

leaked fluid under car

Fuel, coolant, and motor oil are the three essential fluids the engine needs to function. All fluids may enter or exit the combustion chamber if the gasket blows. If this happens, you may notice one or more of the following:

Colored Smoke

Coolant leakage into the combustion chamber is indicated by white smoke. Oil may have entered the combustion chamber if the exhaust pipe emits blue smoke.

External Leakage

A simple coolant or oil leak between the water or oil route and the outside of the engine may happen from a head gasket failure. If the coolant level is allowed to fall too low, it might result in significant engine problems even though they may not show up right away (apart from making a mess). The other problem is that hot exhaust from oil leaks could cause noxious smoke and even fire.

Power Loss

The cylinder's compression is decreased if the head gasket fails in a way that permits the compressed air/fuel to escape. This decrease of compression causes the engine to function poorly and significantly reduces engine output. Typically, this kind of failure is followed by an exhaust leak-like sound.

Discolored Oil

Your head gasket seals in the coolant and oil, so if it fails, the coolant and oil may mix. If the oil has a milky hue, coolant has mixed with it and caused this. This is, unfortunately, the hardest symptom to spot and easy to overlook.

What Is a Head Gasket?

person holding head gasket

The head gasket is the component that closes the engine's combustion chamber, allowing it to create the proper compression required to sustain engine power. Additionally, it stops coolant or oil from leaking somewhere else, guarding against engine overheating and fire.

This means that, unlike any other gasket in the engine, the head gasket must simultaneously seal oil, coolant, and compression from the cylinders. It is the most strained gasket in an engine, making it one of the most vulnerable to failure.

Most manufacturers utilize thin layers of steel to construct a head gasket because it is so essential but also stressed; this increases their durability and sustainability.

Unfortunately, one of the most apparent trends in modern cars is the downsizing of the engines, and the head gasket is no exception. Head gaskets used today are often lighter and stiffer than those used in the past, making them, again, more prone to failure.

How Does A Head Gasket Work?

Your car obtains its power from a crankshaft that rotates, which is connected to internal pistons. The valves that enable the air-fuel combination to enter and exit the combustion chamber are located at the engine's top of the cylinder head.

The head gasket ensures that the combustion chamber retains the compression created by the ignition of the air-fuel mixture. This ignition allows your engine to run efficiently and generate enough power for the automobile to go forward.

The head gasket also prevents coolant or engine oil from leaking into the cylinders, ensuring optimal engine operation and preventing overheating. These two fluids cannot mix or leak at the junction of your cylinder head and engine block for your engine to operate accurately. The head gasket serves as a seal between these two crucial engine components, preventing leaks and preserving pressure.

What Is A Blown Head Gasket?

A blown head gasket results when the seal between the cylinder head and engine block fails. Between these two engine regions, the head gasket seals the coolant route, the oil return passages, the cylinders, and the pistons.

When the head gasket fails, these passages are no longer fully sealed, which can cause coolant leaks, oil leaks, or gases to escape from the combustion chamber. A blown head gasket occurs when an engine overheats, increasing the thermal pressure that places tremendous strain on the gasket.

What Causes a Blown Head Gasket?

hands placing gasket head device


The most frequent cause of a cracked or blown head gasket is the result of an overheated engine. Lack of coolant in the radiator, usually due to a leak, is the primary cause of high engine temperatures.

Sudden Temperature Change

Similar to overheating, the head gasket can blow when there is a sudden, instead of long-term, temperature change. The shock of the sudden temperature difference may lead to a head gasket failure when applying the brake after starting your engine cold. Avoid head gasket failure by letting your car reach the proper operating temperature before accelerating quickly.

Wear Out

Gaskets degenerate over time, just like most other car components. Cars with many miles but no head gasket replacement may experience problems. The materials in the gasket may degrade and cease to seal. After a specific amount of miles, you run a greater risk of experiencing head gasket failure.

Improper Install

If the head gasket was installed improperly, it is unlikely to maintain a seal for very long, if at all. If you had a head gasket replaced yet experienced problems immediately, there might have been a problem with the installation.

Head Gasket FAQ

new head gasket

Can You Drive With A Blown Head Gasket? And If So, For How Long?

Although it is technically feasible to drive with a blown head gasket, it is firmly not advised. Minor issues, such as a rising temperature gauge or smoke from the exhaust, can grow into significant problems very rapidly, especially if coolant or antifreeze gets into the oil.

If you ignore the symptoms for too long, the worst-case scenario is that you might need to replace your entire engine block. A defective head gasket may be repairable if you identify it early enough; this will save you time and money and prevent you from having to purchase a new vehicle.

What Happens If I Let My Blown Head Gasket Go Too Long Without Repair?

Because a head gasket serves as a seal, your engine will lose pressure immediately if it blows, causing a considerable loss of power as a result of the combustion chamber's pistons no longer firing forcefully due to the pressure reduction.

Oil and coolant will begin to leak into sections of the engine where they do not belong, such as the combustion chamber. The motor oil may then dilute due to the coolant mixing with it, making it harder for your engine to lubricate crucial components like your crankshaft or camshaft. This lack of lubrication will quickly result in bearing damage and the possible need for an engine rebuild.

The coolant is no longer available to cool the engine if it is leaking, which is a more critical problem to be aware of if you are driving with a busted head gasket. Suppose you continue to drive without this support. In that case, the engine will quickly overheat, causing severe cracking and harm to your engine, resulting in costly repairs or even a total engine rebuild.

Your engine will suffer more harm the longer you remain driving with a leaky or blown head gasket. If you don't correct it immediately, it might cost you hundreds of dollars in repairs.

How Much Does a Blown Head Gasket Cost To Repair?

Repairing a head gasket can cost thousands of dollars, and some people consider it more cost-effective to scrap an older car with this issue rather than to pay to have it fixed. Although the parts are not typically expensive, head gasket repairs typically cost between $1,000 and $2,000 on average.

In fact, it is often the cost of paying someone to repair the head gasket that costs more than the actual item itself. This process is time-consuming, and mechanics will have you paying well for their time.

Can I Use Sealant on a Cracked Head Gasket?

Sealant can be used to help solve some smaller issues with cracked head gaskets but should never be used as your only option. Understand that this is typically a temporary fix, and you will probably need to do a more thorough repair in the future.

You need to pour a head gasket sealer into the radiator to apply it. You can turn the heating and fan on high and drive the car for 15 to 30 minutes. Heat conduction is how the unique compounds in the gasket sealer function. The head gasket's sealant will look for cracks and openings and then harden.

Replacing a Blown Head Gasket

It might sound a little intimidating to remove the heads from your car to repair a blown gasket, but once you break it down, it's a reasonably doable, if lengthy, process. Some engines' removal and installation procedures result in unique quirks, but the fundamental idea of sandwiching a gasket between the block and head stays the same.

Before you begin, buy a complete gasket package containing gaskets for the intake manifold, exhaust manifold, and similar gaskets because it's typically easiest to replace all the gaskets at once.

Put the car on a lift or stop it from moving by pressing the emergency brake first. Wear gloves to protect your hands and goggles to shield your eyes for enhanced protection.

Before beginning, it is wise to have the vehicle's maintenance manual on hand. Most typical vehicle manuals can be downloaded on the Internet if you don't already have one. The cooling system is then drained, leaving the engine without any liquid.

After that, unplug the battery and remove the fan shroud on the engine's front. The plenum chamber, which is connected to the throttle body, should then be removed. The next step is to remove the fan, which occasionally calls for a specialized, hefty wrench.

The serpentine belt, which circles several pulleys, is then made visible. To make reattaching the belt easier later, take a picture of the pulleys and the routing design. Remove the water pump, pulleys, and belt.

The air conditioning compressor should be unscrewed and moved out of the way since you do not need to remove it to fully get to the head gasket.

Drag the spark plug wires out of the way after unhooking them. It might also be necessary to take the throttle body out. Use a rag to clean anything that is oil-covered or otherwise filthy.

The fuel line may need to be removed. The opposite end of the line can be released by either using a specific tool or holding the line while drawing the connection forward.

Additionally, the cylinder head and intake manifold must be taken apart, but be careful handling them because they are pretty heavy. The valve cover can then be removed by removing all of its mounting fasteners. Due to the exposed valves, the device must be protected from foreign objects entering it.

The next step is to take out the spark plugs. Then, while keeping track of their order and location, loosen each bolt holding the cylinder head in place. Lift the cylinder head out after making sure any cables or hoses do not still attach it. It is best to have someone helping you with this since the space is tiny and hard to maneuver.

The head gasket is a tiny piece of metal perched atop cylinders. Take it off, then look around the cylinder block. Anything chipped or rusty can indicate another problem.

Check for warping of the cylinder head's top by cleaning it before moving on. If everything checks out, clean the cylinder walls with an oil-soaked towel and the cylinder heads with a toothbrush. The new head gasket should then be installed with the right side facing up.

After that, replace everything you have removed by attaching everything in reverse order, ensuring everything is tidy. When installing bolts in the cylinder head, you must adhere to the repair manual's recommended installation order and torque specifications.

It is necessary to add fresh oil and coolant when everything has been reinstalled. Because oil and coolant leaks were probably the first indication that the head gasket had broken, it is frequently a good idea to cleanse the oil and the coolant before adding new ones.


Hopefully now that you have seen a little bit more, you can recognize that, while a lengthy process, you can likely replace a head gasket on your car yourself, especially if you already have some automotive know-how.

Go slow, double check every step, and you can save yourself quite a bit of money. Need more help with typical car problems? Why not check out tips on how to keep your car from overheating or this article on replacing or upgrading your car's muffler.