How Many Spark Plugs Do I Need?

The question of how many spark plugs you need in your vehicle might seem like a simple one, but it’s actually a little more complicated to answer than you may think. It depends on a number of factors, with engine type being by far the most important of those factors.

How does my engine type affect the number of spark plugs I need?

Your vehicle’s spark plug – as its name helpfully suggests – uses a spark in order to ignite the compressed fuel that is in your engine, and through a chemical reaction, convert that fuel into heat, which then powers your car and makes it move.

Each cylinder in your car’s engine requires one single spark plug, so if we know how many cylinders our car’s engine has then we can easily work out the number of spark plugs that we will therefore need.

A single-cylinder engine will require one spark plug, a four-cylinder engine will require four spark plugs, a V6 engine (containing six cylinders in total) will require six spark plugs, and finally, if you’re lucky enough to have a vehicle with a V8 engine (found in very high-end cars and motorbikes), then you will need eight spark plugs, as these engines all have eight cylinders in total.

However, many of us may not actually know how many cylinders our engine has, and therefore how many sparks plugs the engine requires. Fortunately, there are several ways to discover this information which I will detail below.

How do I find out how many cylinders my car’s engine has?

There are several ways to find out how many cylinders your car’s engine actually has, and therefore how many sparks plugs you will need.

The first method will require us to actually open the hood of our car, and take a little look around. Once you’re under the hood, you need to look for the spark plug wires. You should be able to tell that they are spark plug wires as they are usually numbered, and will be either black, blue, or red in color.

Once you’ve found these wires, you will need to count each one – the number of wires equals the number of cylinders your engine has, which is equal to the number of sparks plugs your vehicle will need.

However, it’s possible that you don’t feel too comfortable looking around under the hood of your car, or maybe you’ve checked under the hood and you can’t see any sign of the spark plug wires because they’re simply so well hidden. Well, fortunately, there is a second way to check.

This method will require you to purchase an OBD scanning tool. This handy piece of kit plugs into your car’s OBD port and will give you all kinds of useful information and diagnostic data about your vehicle, as well as the condition it’s currently in. Most importantly, it should tell us how many cylinders our car’s engine has, and therefore how many sparks plugs it needs.

How do you use an OBD scanning tool to determine how many sparks plugs you need?

First, you’ll need to actually purchase an OBD scanning tool. The best place to buy one of these would be either Amazon (make sure you check for a model with good reviews and plenty of purchases), or your local trustworthy hardware store.

Once you have your OBD scanning tool, you will need to plug it into your car’s OBD port. This is usually within easy reach of the driver, often just underneath the steering wheel. Using the device’s instruction manual, you should be able to easily find your OBD port.

Once you have found it, you will need to activate the device. Some models will use an LCD screen to display information, and some will connect to a smartphone app in order to display your car’s information on your smartphone’s screen.

Whichever way it works, it should be very simple for you to navigate to the section containing your car’s engine type. Here, you will find out how many cylinders your car has and therefore how many spark plugs are required (as we detailed in the section above).

Are there any other ways to check how many sparks plugs you need?

If you’re unable to find how many sparks plugs you need by checking for spark plug wires under the hood, and you’re unable to use an OBD scanning tool for whatever reason, there is a final way you can check how many sparks plugs you will need.

This is by checking online. You will need to search for the exact manufacturer and model of your car, and look for any sites online that contain information about the number of cylinders your car’s engine has. This can then be used to determine the number of spark plugs you need.

Some websites will allow you to input your vehicle’s registration number, which will then automatically bring up your vehicle’s manufacturer and model and search for the required information. However, this is only available in certain countries.

The downside to researching this information via the internet is that you must be sure you can trust the site you are using, and it may be that whoever updated that site has incorrect information. If possible, it is best to check the number of spark plugs you need by using the two methods detailed above first.


So, as detailed above, there are several methods we can use to determine how many sparks plugs we need for our vehicle. This is useful information as spark plugs can deteriorate over time, or even blow altogether, and knowing how many your car has can allow you to keep spares in case you ever need to install a new spark plug, or in case you need to take it to a mechanic for a replacement and they don’t have any in stock.

However many sparks plug your car requires, it’s a good idea to ensure your vehicle is regularly checked up by a certified mechanic. A spark plug blowout can be a dangerous and often expensive issue to fix, and it’s better to replace them before they break and cause your vehicle serious damage.


Hi, I'm the initiator and writer of this blog. Cars were and will be my first love, and my favorite hobby, that's why I decided to start this blog and write about my discoveries and techniques to improve my cars or repair them.