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5 Most Common Blown Head Gasket Symptoms

A blown head gasket is one of the most dreaded problems that can plague an average car owner. Annoying and even severe symptoms, high repair costs, and potential for catastrophic engine failure are all there. Although repair costs for a blown head gasket are high in their own right, much more severe problems and even higher costs can be avoided if the problem is diagnosed early on. That’s why it’s important to be aware of the blown head gasket symptoms.

Symptoms of a blown head gasket are typically related to coolant spillage into the engine and its mixing with the oil. Contaminated oil due to coolant spillage then manifests itself through a loss of power, overheating engine, milky-white oil, or white smoke coming from the tailpipe.

The only course of action is to replace the failed head gasket, but as mentioned, that’s typically an expensive process. This article will list the most common symptoms of a failed head gasket and answer the questions about the head gasket repairs and their costs.

What is a Head Gasket?

Before we proceed with the symptoms of the blown head gasket and its solutions, let’s take a look at what the head gasket actually is and what’s its purpose within the engine.

Internal combustion engines consist of a cylinder block where you can find the pistons and cylinders and a cylinder head where the valves and camshaft reside, among others. A head gasket is a specially designed seal that slots between the cylinder block and cylinder head.

The in-line cylinder engine design accommodates one gasket per engine, while the V-engine design sports two gaskets.

What Does a Head Gasket Do?

A head gasket serves as a sealant that prevents the engine oil and coolant from escaping the cylinder head while simultaneously preventing the combustion gasses from entering the cylinder head.

Sandwiched between two complex compounding parts, the head gasket has to withstand friction between them. Moreover, there’s the issue of their constant shrinking and expansion. Finally, it also needs to fulfill its primary function of sealing the two.

Considering how a head gasket operates under extreme conditions, its integrity must remain impeccable at all times. That’s why modern head gaskets typically feature a multi-layered steel design that’s more durable than the past designs when copper and composite gaskets were prevalent.

What is a Blown Head Gasket

A blown head gasket refers to a head gasket that’s structurally compromised. A compromised head gasket won’t be able to fulfill its primary purpose of sealing the cylinder head from the block.

Depending on the exact point of head gasket failure, a vehicle may exhibit several problems. These problems manifest themselves through various symptoms, which are the focal point of this article.

Blown Head Gasket Symptoms

Here are five of the most common symptoms of a blown head gasket.

Coolant loss

engine coolant loss
Photo by Envato Elements

If your car is burning through coolant, one of the possible culprits can be a faulty head gasket. Especially if there’s no visible source of the leak, which would mean that the coolant is burning and evaporating.

There may also be a visible leak between the cylinder head and block. Some compression can also escape the engine at such points, creating small bubbles in the process.

Coolant loss is the least severe of blown head gasket symptoms. However, the symptoms will only get worse if left unchecked hence it’s imperative to diagnose the problem as soon as possible.

Engine overheating

engine overheating is the most common of blown head gasket symptoms
Photo by Envato Elements

While an overheating engine can be a cause of a failed gasket, the latter will always lead to engine overheating.

Most commonly, the overheating will be caused by the loss of coolant. However, that’s not the only possibility. Combustion gasses escaping into the engine’s cooling system or coolant leaking into the cylinders and getting burned off will also lead to engine overheating.

Driving a car that’s constantly overheating can lead to additional problems. Warped cylinder heads or a damaged catalytic converter are some of them.

Poor car performance

broken down car
Photo by Pixabay

A loss of power can be another signal of a blown head gasket, but also of many other issues.

If a gasket fails in such a way that it allows the compression to escape, the performance of a car will suffer. This typically happens if a gasket fails between two adjacent cylinders and the compressed air/fuel mixture is allowed to escape via the valves of a combustion chamber.

Aside from losing power, the engine will exhibit rough idle, stalling, and even knocking.

White exhaust smoke

car smoke
Photo by Pixabay

White exhaust smoke indicates a burning coolant due to a leaking head gasket.

If a coolant makes it into the combustion chamber, it will burn out and turn into vapor which then ends up in the car’s exhaust system. Something similar happens if oil gets into the combustion chamber, only in that instance, the exhaust smoke is blue.

Aside from damaging the engine itself, coolant or oil vapors can damage the catalytic converter over time.

Oil contamination

car oil

A leaking head gasket can allow the mixing of oil and coolant, leading to potentially disastrous consequences.

If coolant takes grey or brown coloring of engine oil and appears milky in texture, chances are you’ve got a blown gasket. Oil contaminated with coolant will likewise change its appearance and become frothy. Needless to say, both will lose their properties, leading to many possible issues.

Contaminated oil loses its lubrication qualities and leads to damaged engine bearings. This, in turn, may lead to catastrophic engine failure, setting you back thousands of dollars. Likewise, the contaminated coolant won’t be able to do its primary function of cooling the engine.

Final Words

A faulty head gasket can lead to numerous serious problems, and blown head gasket symptoms shouldn’t be overlooked. In the least severe cases of mere coolant loss, the car will run fine for a while, but that doesn’t mean the issue should be neglected. In the more severe cases, such as oil contamination, damage can be so extensive that only complete engine replacement might be an option. If your car exhibits any of these symptoms, it’s imperative to take it to a mechanic immediately. Otherwise, you’re risking exacerbating the problem and damaging numerous engine, exhaust, and cooling system parts.


How much does a blown head gasket repair cost?

A blown head gasket repair will typically set you back between $1,000 and $2,000, depending on the make and model of your car. Note, however, that more expensive models with complex engines could require even more.

The parts aren’t the main issue here as they’re relatively affordable – especially considering the total costs. Due to the complexity and time-consuming nature of engine removal, disassembly, and assembly, it’s the labor costs that drive the totals into the aforementioned figures.

Why does a head gasket fail?

The most typical reason for the head gasket’s failure is overheating. An overheating engine will undergo expansions along the cylinder block/head line, which, in time, creates a separation between them and compromises the head gasket’s seal. Such a leak in the head gasket typically develops over time.

Stronger or premature detonations within the combustion chamber can also cause a head gasket failure. Over a prolonged period of time, they’ll allow for compression leaks, effectively reducing the head gasket’s effectiveness.

Can you drive with a blown head gasket?

Yes, it’s usually possible to drive even with a blown head gasket, but that doesn’t mean you should. The head gasket seal is integral for the vehicle’s optimal performance.

Having a faulty head gasket seal will, as above explained, eventually lead to serious engine problems and even a potential catastrophic failure. The consequences of driving with a blown gasket for an extended period of time, as such, are disastrous.

How to prevent a blown head gasket?

The best way to prevent a blown head gasket is to keep your engine coolant in check. Furthermore, you should pay attention to any potential additional source of overheating.

The further your car’s odometer reaches, however, the higher the chance of a head gasket failure becomes. At some point, it might happen nevertheless.

Nikola Potrebić

Nikola enjoys digging into history and finding everything he can about rare, limited-run, and special-edition models of the bygone muscle car era.

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