Is A Blown Out Spark Plug Risky?

You should never take the blown-out spark plugs lightly because  8% of Americans have road accidents for that, according to the National Safety Council (NSC). You must ensure that the spark plugs are doing fine when you drive. So, is a blown-out spark plug dangerous? Should you keep driving with that?

Of course, blown-out spark plugs are dangerous for your vehicle and you should never keep driving with them. The spark plugs ensure the right combustion process and provide the initial spark to your engine for getting started. When they’re blown out, you’ll face difficulty in starting the vehicle.

Not only this but also there are more smaller and bigger issues that might be caused by blown-out spark plugs. For this, you must have a clear idea about how a spark plug blows, what are its symptoms, and how you can fix and prevent the issue.

Let’s go on to know all the above-mentioned points from this article.

Can You Drive With a Blown Spark Plug?

You should never drive with a blown spark plug because it can cause extreme damage to the engine. If you’re sure that the spark plug is blown when driving, it’s best to stop the car right away.

If you keep driving, it will make the spark plug scorching hot and you won’t be able to pull it out as needed.

But in the very first place, will you be able to drive the car with a blown-out spark plug?

Well, the answer depends. If your car has a single-cylinder engine, a blown spark plug will not let it start at all. It’s because your engine needs an initial spark to start the combustion work and it ensures the spark plug.

A spark plug fits on the cylinder heads to produce the initial electrical jot that starts the air/fuel combustion process.

So, having only one cylinder in a vehicle will not allow the engine to start when the spark plug doesn’t work. But if your car engine has multiple cylinders, it’s possible to drive the car for a while.

Still, there will be several problems if you continue driving since the spark plug will not successfully convert the fuel into energy. It will lead your car to have low gas mileage.

And, know that there could be bigger risks including instead of just losing some fuel efficiency. If you don’t pull over immediately when the spark plug blows, it may damage the other parts of your vehicle severely which will increase the repair cost.

What Causes The Spark Plugs to Blow Out?

The biggest reason for a blown-out spark plug is that the plug was loose after you installed it. Since the plug backs out further over time, there will be a lack of threads to hold the plug in place.

Eventually, it leads the spark plugs to shoot out of the wholes when you keep the engine running.

Just like the loose spark plugs, tightening them too much can also make the spark plug blow. In this case, the spark plug is unable to transfer electric charge to the engine.

Another reason can be a broken wire in the ignition coil. If this wire is broken, it can cause sparks to blow out of the plug instead of being directed towards the spark plugs inside the engine.

Other causes include worn or damaged parts inside your vehicle’s engine that affected how well electricity traveled through those parts. Besides, wet weather conditions can create road salt deposits that can block electricity from reaching the spark plugs.

Sometimes, the cause is simply an issue with the electrical system of your vehicle – for example, if there’s a problem with your fuse box or the ground cable. In other cases, a spark plug may simply fail due to excessive heat – as, if your engine is running hot.

Moreover, spark plugs get wet from the coolant, gas, or oil which also can cause them to blow out.

What Are the Symptoms of a Blown-Out Spark Plug?

It’s pretty easy to tell whether your car has blown-out spark plugs or not because in most cases, it makes a sound like a gun going off.

Also, the sound is extremely loud and easily noticeable. Your engine may even sound awful if it still runs. So, when you face this, look under the hood to find out what’s wrong with the spark plug. And, you’ll notice how the plug is dangling by the wire.

Some other symptoms you might notice when the spark plug blows out. Scroll down for the details.

Unusual Acceleration

After putting your foot on the accelerating pedal as usual, if you notice that your car is having stutter issues and it’s not going up, there could be blown spark plugs you need to take care of.

It’s because damaged spark plugs do not let the carburettor do its job so it will not pick up the speed just like it usually does. In such cases, spark plugs are not capable enough to ignite the combustion chamber so you find it difficult to start the engine.

Engine Misfiring

Your car engine frequently misfires when there are damaged or blown-out spark plugs. You will face poor car performance with loss of power when the engine misfires.

But remember that, there can be other reasons for engine misfiring and blown-out spark plugs are one of them. The issue can be anything like cheap fuel in the engine, or a damaged ignition coil plug cap. So, it’s best to get your car checked by an efficient mechanic when it happens frequently.

Poor Fuel Economy

When you spend more fuel than before, there can be a problem with your spark plug. When there are blown-out spark plugs, your engine needs to work harder because the fuel doesn’t burn effectively in the combustion chamber.

So, when the spark plugs go off, it adversely affects the burning rate and the combustion reaction takes a toll on the fuel consumption.

Therefore, if you notice your car’s fuel economy takes such serious hits, get the car checked as soon as possible.

Engine Signal Lights

You may already know that beeping or popping the signal light of your car means there’s something wrong in there. It can indicate tons of other issues but it can also indicate that there are blown-out or damaged spark plugs.

So, if you notice such a thing, consult a mechanic to be sure about what’s exactly going on.

Engine Knocking

You may hear knocking sounds from the car engine whenever you turn up the speed if there’s a blown-out spark plug in your car. When the plug can’t detonate properly and ignite all the gas, chances are the fuel and vapour can fire.

When this issue exists, you will hear your engine make a knocking sound. Don’t waste much time in such cases, get your car checked by an expert.

How Much Does It Cost to Fix a Blown-out Spark Plug?

If you want to get it fixed by yourself, you only need to spend on the repair kit only which costs around $300-$600.

But if you have never done that and don’t want to take the DIY risk, you need to take your car to a repair shop. Generally, shops charge anywhere between $800-$1,000 including the kit price and service charge.

So, yes, how much it costs to fix a blown-out spark plug is up to your decision.

How Can You Prevent a Spark Plug Blowout?

There is no guaranteed way to prevent a spark plug from blowing out but there are some simple precautions you can take.

  • It’s a must to install spark plugs the right way.
  • Never use the lower torque specs in older Ford service manuals; you must get the right-size plugs no matter what.
  • Don’t keep the plugs loose or tighten them too much.
  • It’s best to always use hand force when you deal with the plugs because using any tools will cause brutal force that may damage the plugs.
  • Don’t take engine noises like ticking or knocking lightly. You should immediately stop driving and check the engine whenever it happens.
  • Your car should have an optimal torque level when you drive it. Find the ideal torque reference for your car (read the owner’s manual for this) and make sure there’s no mess.

How To Fix Oily Spark Plugs?

Spark plugs often become oily if any tube in its vicinity leaks. Oily spark plugs do not cause any major problems but do produce a burning odour or smoke. In this case, you can fix the oily spark plug by following the steps below.

  1. First, unplug the spark plug wires and set them aside.
  2. Now, remove the clamps from the hose to the valve cover and pull them.
  3. Remove any wiring harness you notice on the way to remove the valve cover.
  4. Since the spark plug tube is built into the valve cover, so you need to remove the valve cover to replace them. So, now remove the valve cover.
  5. Sometimes the valve cover gets stuck. In this case, take the help of a screwdriver.
  6. Find the leaked seals. Remove old spark tube gaskets.
  7. Add new spark tube gaskets. Before that, place a sealer over the gaskets, then place them on top of the spark plug tube.
  8. Tighten the bolts again. Then reinstall the spark plug wire, hose – everything.
  9. If any oil spills on the engine while completing the tasks, clean it with a brake cleaner. Otherwise, the car will smoke while starting the engine.
Blown spark plug Infographic

Frequently Asked Questions

How Far Can You Drive With a Blown-out Spark Plug?

Generally, you can drive to the nearest service station or mechanic and have the plug replaced. However, if you experience any of the following problems, it may be best to take your car in for repair: power steering is difficult to control; warning lights appear on the dashboard; engine does not start; car rides rough.

What Happens if a Spark Plug Blows?

If a spark plug blows, the resulting explosion can damage vehicle components including the engine, drivetrain, and exhaust system. In extreme cases, this explosion may result in serious injury or even death. If you experience any of these symptoms after your car has been blown out by a sparkplug malfunction please take it to an automotive specialist immediately for inspection and repair.

How Frequently Should We Replace the Spark Plugs?

The best way to determine how often your spark plugs need to be replaced depends on the type of driving you to do and how well your vehicle is maintained. Generally, it is recommended that spark plugs be replaced every 30,000-90,000 miles (48,000-144,000 km).

Can I Drive With a Blown Spark Plug?

If your car is inoperable due to a blown spark plug, you should take it to an automotive specialist for repair. Driving with a blown spark plug can lead to safety issues and may even result in injury or death.

Can You Run an Engine With a Broken Spark Plug?

No, you cannot run an engine with a broken spark plug.

Can You Drive With Burnt-out Spark Plugs?

Yes, you can drive with burnt-out spark plugs provided that the engine is able to start. However, if the engine does not start, it is best to take your car in for repair. Blown spark plugs can lead to a dangerous situation where the engine will not restart. Driving with a broken spark plug can lead to safety issues and may even result in injury or death.


While it may not be safe to drive with a blown spark plug, you can still drive safely. Driving while your engine is not running smoothly can be dangerous, and even deadly, so it is important to take the necessary precautions to ensure your safety. In addition to checking your spark plug, it is also important to have your car inspected regularly and make sure all the other components are in good working order. Finally, never drive if you are under the influence of alcohol or drugs, and always wear a seatbelt.

2 thoughts on “Is A Blown Out Spark Plug Risky?”

    • Yes, you can replace blow out the spark plug and drive. Remember replacing means removing an old plug and installing a new one.

      You cannot just remove blown out the spark plug and drive. You will not get your vehicle started without a spark plug.


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William Baldwin

This Is William Baldwin, The Founder & Managing Editor of this website. Me and my team share automotive tips, tricks, and news

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Talha Atta

Talha Atta, a Mechanical Engineer and experienced technical content writer and editor at with a passion for the automotive industry.