How to Break a Window With a Spark Plug


It’s a metal device placed inside an engine to improve combustion.  Its function is to provide good, strong, and reliable sparks that ignite the cylinder’s fuel. A spark plug does not look like any other object because it’s been designed that way for its special purpose. In addition, other objects can be used as replacements for a spark plug (a piece of metal or wood), but they don’t work in the same fashion.

How to Break a Window With a Spark Plug

The essential difference is that a spark plug has a hole drilled through it, and this hole provides more contact surface area between it and the air/fuel mixture than a solid object would – thus improving efficiency. Sometimes in terms of emergencies, you might need to break a window with a spark plug. So today, I will discuss a process on how to break a window with a spark plug. So let us get started.

Step-wise Guide on How to Break a Window With a Spark Plug

Step 1. Find a Spark Plug:

This is the toughest step as spark plugs are not common, and one has to look hard for them. Else use anything heavy you can find lying around in your house or office – bricks, stones, even tables can be used as long as they have a flat surface. If you live in rural areas (or the suburbs), try asking at local garages if they have any spares lying around unused.

Step 2: Find Something Metal and Pointy Enough to Stick Into the Hole of The Spark Plug:

Although there are some dielectric tools out there available in the market specifically designed for opening windows without breaking glass pieces into shards all over your car’s interior space (and they are very effective), there’s no harm in using a thin and sharp object like a screwdriver, knife or even an old razor blade. It will be comparatively easy to use – jam it into the spark plug hole as far as you can comfortably stick it in without breaking the glass itself. Then apply some force and pull your AC/DC convertor out of your car.

Step 3: Set The Spark Plug  On The Window:

This is where most people fail when attempting this method. You cannot just throw away something heavy from inside a moving vehicle while traveling at high speeds on highways! Instead, try to get off the highway or find a place where you can safely stop, park your car, and set an AC/DC converter on your car’s window.

Step 4: Start The Engine:

Once everything is in place, switch on the engine and wait for a while until the exhaust inside the converter starts emitting strong heat. This will make your work easier when it comes to breaking the glass.

Start The Engine Of Car

Step 5: Use A Hot Surface To Directly Tap On The Window:

As soon as you hear a dull thud, tap vigorously around the window using anything that can withstand high temperatures. It will be much easier to break the glass now as it will not take much force to crack a spark plug-heated surface! Note: Glass shrapnel can fly off in every possible direction once it breaks, so try steering away from the path of the flying bits.

Step 6: This Works Better On Side Windows:

In the case of backseat passengers, use a sharp object to poke through the glass at your preferred position and then break it using the method described in step 5. Else for side windows, you can take a long sheet of paper and tape it over half of the window pane such that it covers up most of your vision while seated inside the vehicle.

Now gently push outwards on both sides of this makeshift paper mask so that one side starts peeling off. Keep doing this until you have peeled off enough paper to see through but still cover enough part of your field of vision as not to make things difficult for yourself when handling hot exhaust gases.

Precautions while Performing How to Break a Window With a Spark Plug

  • The window should be closed tightly, and the “Drapery” should be drawn for better effect.
  • While throwing the spark plug, ensure that you are at a safe distance from the window, i.e., 6 to 8 feet away, to avoid any mishap or injury due to broken glass pieces/debris falling on you.
  • Aiming shouldn’t be difficult here as one might think it is because the physics behind it is pretty simple. Still, its effectiveness in breaking a window can never be underestimated as it has been proven by many incidents (like Car Break-In) in the past years where breakers used this trick successfully to break windows of their car while they were driving or parked somewhere else with people around them since no one would ever expect someone to try breaking a window with something like that and hence no one would even notice or expect it at first.
  • Some people prefer using a ball-point pen instead of a spark plug, but the efficiency is still debatable and not as effective as a spark plug, so I suggest using a spark plug which can really do the job in few tries!
  • For better effects, you may use two dry cell batteries wired together through some wire (i.e., cut out the negative terminal of the first battery from its cover, attach them both, i.e., the positive terminal of the second battery with the negative terminal of the first battery) and connecting it to a car door electric lock opening mechanism by attaching the wires to its terminals then while aiming at the window throw the spark plug towards it and as soon as it hits the glass, turn on the switch (i.e., connect both wires to the positive terminal of the battery) which will generate a powerful electromagnetic pulse through the wire attached to door’s electric lock thus creating an intense magnetic field causing the severe voltage in the spark plug triggering an electric arc which would melt/burn its insulator/s producing a flash of dazzling light followed by loud explosion or bang sound like a gunshot.
Spark Plug

Why Does the Spark Plug Work So Well at Breaking Shattered Glass?

To understand why a broken spark plug is so good at breaking glass, we must first understand how the spark plug works. The spark plug usually has an electrode gap of about .030-inch (.76mm). When current flows from the ignition coil through this small gap, high voltage and high temperatures are generated.

A breakdown of the air in between the electrodes occurs, which produces an ionized path for electricity to flow called a streamer. If any combustible material is within .030-inch (.76 mm) of either side of these terminals, it will ignite. Unfortunately for automobile technicians, most automobiles have many dozens or even hundreds of these spark plugs – all ready to break apart with relative ease when they fail (burn out).

How to Break a Car Window to Save A Life:

There will be two vertical metal strips, one on each side, running from top to bottom.  They usually run about 2″ back from the edge of the window itself.  Looking at them, you should see that they angle in toward where the rubber seals are for the doors when closed.  Where they meet those seals is a spot that’s easy to break with almost anything, including your hand if you’re strong enough and have some protectors on so you don’t cut yourself accidentally.

Before attempting this method, be sure there isn’t any other way into the car: windows not rolled up properly or openable vents, etc… If there is no other way in then, it’s time to break the window.  Using a standard glass-breaking hammer [the ones you see cops use to smash windows in movies], tap on each of the vertical strips one or two times in quick succession.  If there are no horizontal bars, then this is all that’s needed!

As long as your hand is in contact with the top of the strip and not touching any other part of the glass, you should be safe from getting cut by flying glass when it breaks.  In fact, holding onto it will keep it from shattering too far out into the car, making it easier to remove from inside.  Once it had broken off about 2″ worth (make sure you didn’t hit any metal framework underneath), simply loosen your grip and let gravity pull the rest out.

Try To break A Car Window to Save A Life

Safety Tips While Using Spark Plug:

  • Keep your hands, face, and other body parts away from the mouth of the spark plug while it’s running.
  • Always wear safety goggles to avoid eye injury caused by flying metal shavings during its operation.
  • Never try to insert a new plug without taking out the old one first; this will damage or break the insulation on the ignition wire in case if you hit that with a mallet resulting in a short circuit inside the spark plug hole, causing sparking within engine compartment which may cause an explosion!
  • Never try to remove a new spark plug without taking out the old one first; this will damage or breakage the spark plug body and ignition wire insulation due to misalignment during its removal.
  • The use of rubber gloves is highly recommended, especially in military, police, and law enforcement agencies, whenever handling of Spark Plug takes place because accidental short circuits on internal metal parts can cause explosions.
  • Always keep your hands dry and clean while working with spark plugs so that you don’t accidentally short circuit any live wires leading to sparking, which might harm you unknowingly!


I hope you have learned properly how to break a window with a spark plug. Ensure proper safety while performing the process. Thank you and have a nice day!

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