Can You Drive with a Blown Head Gasket? Information to Stay Safe!

You had a feeling that something was wrong several days ago when your vehicle started overheating, but you told yourself that you would take care of it later.

Today, you started seeing white smoke coming out of the exhaust, you checked your engine oil and it looked murky and milky, and you finally stopped driving your car because you felt like it was down on power.

All these signs point to a potential blown head gasket. You know that a replacement head gasket is an expensive repair job, and you really need your car for the time being to get back and forth from work and to pick up the kids at daycare.

Mechanic holding a new head gasket to replace the blown head gasket

So, you’re now asking yourself if it’s safe to drive your vehicle with all of these problems. The situation is already bad, but the potential to go from bad to even worse is always a possibility. At least, that’s what you think.

Can you actually drive the car with a cracked head gasket? We’re going to answer this question in great detail in this article.

What Is a Head Gasket?

A head gasket is a thin piece of material – often steel – that seals the engine block to the cylinder head, which allows engine coolant and engine oil to circulate through the engine without mixing together, while also allowing proper compression and combustion within the combustion chamber.

When a head gasket blows, it means that this seal has been broken, damaged, or cracked, and will allow compression to escape, improper combustion to occur, or engine fluids to infiltrate parts of the engine through which they were not designed to flow.

This could cause severe engine damage over time, and engine repair might not even be a choice for you at that time – a potential engine replacement could become the only solution.

What Could Cause a Blown Head Gasket?

There are four main things that tend to cause the head gasket on your vehicle to fail, and those are:

  • Heat
  • Pressure
  • Age
  • Vehicle design.

Your Engine Consistently Gets Too Hot

If your vehicle develops a coolant leak, it will be a prime candidate for an eventual blown head gasket.

Even not changing the oil in your vehicle when a schedule is due could lead to overheating because of poor internal lubrication, which could cause your engine to run hotter than it normally would.

Overheating causes the metal parts within the engine to expand, eventually leading to a crack or break in the head gasket.

The Pressures in Your Engine Are Higher Than Normal

Engines are designed to withstand tremendous amounts of internal pressure, because every time the air-fuel mixture combusts, there is literally an explosion that occurs within the combustion chamber.

When those pressures become too great, most often because of a combustion timing issue or improper air-fuel mix called engine knock, a break in the head gasket can form.

Your Vehicle Is Very Old or Has High Mileage

Even the best things wear out with time. A vehicle that has been well used will eventually wear out, and that includes parts like the head gasket.

This does not mean that every high mileage vehicle that is more than twenty years old will eventually blow a head gasket, but the chances of this happening on such a vehicle are definitely higher.

Your Vehicle Is Prone to Head Gasket Failure

Some vehicles are manufactured with design flaws. Vehicles with engines that are designed poorly, or engines that use less durable head gasket materials, are more likely to encounter head gasket failures than others.

Subaru is notorious for manufacturing vehicles with a high rate of head gasket failure because of the materials they use in older models and because of the engine design, which is a flat four-cylinder layout as opposed to the inline or “V” engine layout.

Can You Drive with a Blown Head Gasket?

If your car’s head gasket is blown, the answer to this question is more complicated than just a simple and straightforward “yes” or “no”.

There are many signs that vehicles may exhibit over time that point to blown gaskets.

Things like white smoke coming out of your exhaust, engine overheating, the presence of coolant in your vehicle’s oil, and the loss of coolant without a visible leak all point to a potential problem.

Your check engine light may even come on, because these things may cause other systems to fail as well.

Even all of these things put together may not cause your vehicle to abruptly stop running; therefore, you can often technically drive your vehicle with a blown head gasket. This is especially true if, in your case, you know for a fact that a head gasket sealant temporarily solves the issue.

The better questions to ask are “Should I drive with a blown head gasket?”, and “Is it safe to drive with a blown head gasket?”

The answer to both of these questions is much more straightforward: Absolutely not!

When Should I Drive with a Blown Head Gasket?

When all the signs point to head gasket failure, you should only drive your vehicle in an emergency situation or when you need to get it to a repair shop that is close.

Nobody wants an emergency to occur, and nobody wants any sort of vehicle trouble on the highway in the middle of nowhere. Should this occur, you should immediately take your vehicle to closest repair shop or call a tow truck to transport your vehicle so that the problem can be addressed immediately.

If you happen to be closer to home at the time, and you know your vehicle has a cracked head gasket, it is still recommended and much safer to call a tow truck.

If the repair shop is very close, and no towing option is available, you may have to drive it to the nearest shop.

What Could Happen If I Drive with a Blown Head Gasket?

Prolonged running of the engine with a known head gasket issue can cause serious engine problems.

A head gasket replacement is already one of the most expensive repair jobs a vehicle can undergo; so preventing further damage and a more costly repair is crucial to both your safety and your wallet.

Engine Fluids Will Leak into Places They Are Not Supposed to Be

The whole point of the head gasket is to keep engine oil and coolant separate while allowing them both to circulate through necessary portions of the engine.

If it fails, this cannot occur, and coolant could leak into the engine, or it could cause the oil to leak into the coolant system.

High Cylinder Head Pressures Could Cause Other Failures to Occur

Another crucial job of the head gasket is to contain the high pressures within the combustion chamber.

If this pressure is not contained and spreads to within the cylinder head itself, other components within the cylinder head, including valves, spark plugs, and their own gaskets, may be compromised and could also require replacing.

Coolant Could Prevent Spark Plugs from Working Correctly

Leaking coolant that makes its way into the engine as a result of a blown head gasket may leak onto the spark plugs, preventing them from firing, and ultimately causing a misfire or preventing your engine from running at all.

Catalytic Converter Damage Could Occur

A potential direct result of a head gasket failure is a coolant leak into the catalytic converter. This could lead to the contamination and clogging of the catalytic converter, which could result in another costly replacement.

A misfire that develops as a result of clogged spark plugs from a coolant leak could also cause fuel to get pumped into the catalytic converter. The same type of damage could occur as a result.

Engine Sensors May Become Damaged

Modern engines are loaded with sensors and monitors to compensate for harsh or unusual conditions within the engine. Despite this, sensors like the engine knock sensor could be damaged or fail as a result of a blown head gasket.

Sensors are only able to compensate for a problem for so long, and will not be able to solve a problem completely. As a result, sensor failure may result due to overuse, continual compensation, or because of a domino effect which spreads to other engine systems.

You May Be Burned or Your Vehicle’s Engine May Catch on Fire

Have you checked under the hood lately?

Any head gasket leak that causes oil or coolant to exit the engine has the potential to cause personal injury or a vehicle fire.

Opening the hood when coolant is leaking outside of the engine could cause burns from the intense heat of the liquid. Additionally, any leaking fluids outside of the engine could contact the hot exterior surface of the engine and ignite.

For safety purposes, ensure you have a properly functioning vehicle fire extinguisher in your car at all times.

Your Vehicle May Not Start or May Stall

Coolant fouling the spark plugs or ponding of coolant within the combustion chamber due to a blown head gasket will often prohibit the spark plugs from creating a spark and igniting any kind of air-fuel mixture.

A blown head gasket could also prohibit proper compression within the combustion chamber, because pressure could be escaping from the leak, causing your vehicle to stall, or not being able to get the car started altogether.

Eventual Total Engine Failure Could Occur

Improper lubrication within the engine, rust from coolant buildup with the combustion chamber, and improper pressures within the engine could all result in a complete engine rebuild if not addressed as soon as signs of a head gasket failure manifest themselves.

Watch this video for symptoms and consequences of driving with a blown head gasket.


What Else Do I Need to Know About Driving with a Blown Head Gasket?

Know the signs of head gasket failure and act quickly to address the issue. This will not only prevent an already expensive head gasket repair from becoming even more expensive, but it will prevent you from having to drive your vehicle with a fully blown head gasket in the first place, which is a serious safety risk.

If anything can be done to avoid driving your vehicle with a cracked head gasket, you should do it.

Even in the absolute worst-case scenario where you absolutely have to get behind that steering wheel, you should not drive your vehicle for more than a few miles to a repair shop. Remember, it is never safe for you or your vehicle to drive with a blown head gasket.

Preventative maintenance is always the key to avoiding a blown head gasket, and therefore, finding yourself in a situation where you have to drive with one.

Know which vehicles are prone to head gasket failure, and know when to replace the head gaskets on any vehicles as soon as the signs of failure manifest themselves.

If you ever have any questions concerning your head gasket or you are unsure whether the one you have needs to be replaced, always ask a certified mechanic for advice.

Wrapping it Up

Replacing a head gasket is one of the costliest vehicle repairs a car owner can encounter. As a result, many people neglect to change a bad head gasket, even if all the signs point to total failure.

Ignoring a blown head gasket could not only cause a more costly repair bill than it already may be, it could also force you to buy a whole new vehicle and could cause serious personal safety concerns for you and your family.

Understand and know the ramifications of not replacing a blown head gasket as soon as the signs point that way, and fix the issue as soon as problems start to arise. That way you, your family, and your vehicle are kept as safe as possible at all times!

I've had a passion for cars since 8 years old, and been a subscriber to Auto Week magazine since my 10th birthday. Ever since I turned old enough to drive, I have driven as many vehicles as possible, while teaching myself how to perform maintenance and upgrade work on every vehicle I've owned. For the past 10 years, I've been honing my skills as a vehicle hobbyist, in recent years also enjoying writing car reviews, opinion articles, vehicle how-tos, car-buying guides, and even provide individual consultations for those who need car-buying advice. In addition to writing for Vehicle Scene, I currently write for Autolist, and also own and operate my own vehicle blog website, The Unlimited Driver.

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