What Does It Mean To Blow a Head Gasket?

Blowing a head gasket is among the more terrifying causes of a check engine light. Some people actually avoid vehicles that are notorious for being susceptible to this issue, whether they deserve such a reputation or not. Even drivers without an extensive knowledge of cars know this is an expensive repair. All vehicle owners should learn the symptoms of a blown head gasket, the amount of time they can drive with this problem, and the ways to prevent it. Finding this information out can save drivers money by avoiding this engine disaster.

What Is a Head Gasket?

The head gasket acts as a seal between the head of each cylinder and the engine block. Your powerplant works by using the force of a contained combustion of fuel to drive the piston. The gasket works to contain the combustion, so your engine directs its power more efficiently. It also acts as a barrier between the fuel, oil, and coolant. Every fluid in your vehicle has its own job and mixing them – such as oil getting into your combustion chamber – could cause catastrophic problems.

You can think of the combustion in your engine as a mini-explosion. The head gasket has to be durable to endure millions of these explosions over its lifetime. To resist these forces, a gasket is made from steel or tough composite materials. Some high-performance models use copper to form a more complete seal that offers better heat dispersion.

What Are the Symptoms of a Bad Head Gasket?

Because of the critical jobs performed by this seal, it’s often easy to tell when it’s blown. Look for the following signs of bad head gasket if you think it’s having problems:

1. The engine is overheating

This indicates that the coolant has leaked to the point where it can’t effectively cool the engine. If you see your temperature gauge is unusually high or notice a service light, this could be why.

2. The engine isn’t performing well

As previously mentioned, the head gasket makes your powerplant run more efficiently. If the seal is loosened, you might note a rough idle and lack of power.

3. The coolant is low with no obvious leaks

Your antifreeze can leak into a variety of places with a blown head gasket. Because some aren’t immediately obvious, you may not locate the leak until your coolant level runs low. This is another reason why checking your fluid levels should be part of your maintenance routine.

4. The oil looks pale and milky

When the barrier between your engine’s fluids is compromised, it allows them to mix. As coolant leaks into your oil, it alters the color and consistency. Not only is it no longer cooling your engine, it’s diluting your oil and making the lubricant less effective.

5. The tailpipe is producing white smoke

When coolant leaks into your combustion chamber, it produces steam. The white smoke coming from your exhaust is actually water vapor and glycol.

6. The exhaust manifold has coolant leaking below it

When the antifreeze is leaking outside the engine, it can create a small puddle on the ground. The color and smell will help you differentiate it from water produced by condensation.

7. The radiator or overflow tank has air bubbles in it

If the gasket between the coolant passage and combustion chamber fails, air can be pushed into your cooling system. A particularly large air pocket could even block coolant from circulating.

8. The spark plugs are fouled

When the coolant gets into the combustion chamber, it can cause problems with your spark plugs. In rare cases, this could even cause misfires. This could be a symptom of other issues, so look for other signs of a blown head gasket.

Even if these symptoms don’t point to a bad seal, you should get them checked out. These are all signs of a major issue with your vehicle.

Can You Drive With a Blown Head Gasket?

As indicated by the symptoms above, it’s not unusual to drive with a bad seal. While you can continue to use your vehicle, you should avoid doing this unless absolutely necessary. A busted head gasket will only get worse, damaging more systems as it continues to fail. As poor temperature regulation is one of the side effects of this problem, your car can eventually sustain severe damage from an overheated engine.

How Much Does a Head Gasket Replacement Cost?

The price of this repair can vary a lot from vehicle to vehicle. Even high-quality copper gaskets are relatively inexpensive, making the actual replacement part the cheapest aspect of the process. As with many automotive repairs, the bulk of the cost actually goes to labor. The overall price depends on many factors including the severity of the damage, number of cylinder banks, presence of overhead cam VS pushrods, and other parts damaged.

If you’re a veteran mechanic with an extensive tool collection, you likely feel comfortable tackling this job. For those of you who aren’t, this fix should be left to the pros. Drivers are better served focusing their efforts on preventing blown head gaskets.

How Do You Prevent a Head Gasket From Blowing?

One of the most common causes of this issue is overheating the engine. Previously, it was discussed that copper is a high-performance gasket material because of its heat dispersal properties. This is because high temperatures can damage the seal. Ensuring that you have adequate coolant levels can help prevent this. Regular oil changes and using an oil grade rated for your environmental conditions will also help with this.

If your vehicle has a turbocharger or supercharger, keep your combustion chamber pressures low. These mods put a lot of stress on the gasket, which can eventually cause it to blow. Leave the boost level at the factory setting to prevent excessive chamber pressure.

As with most problems, an ounce of prevention is worth a pound of cure and it’s also significantly cheaper. Staying up to date on oil changes and service milestones saves cash in the long run by avoiding major repairs. If you feel confident in fixing your own head gaskets you can skip high labor costs. Find superior replacement parts and the tools to do the job at your local AutoZone or our online store.

Advice, how-to guides, and car care information featured on 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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