How Many Spark Plugs Do I Need?

It’s asked all the time…. how many spark plugs do I need for my vehicle or engine. In short the answer is simple!

The amount of spark plugs you need will depend on the size of the engine. Typically you will require 1 spark plug for each cylinder on the engine. A four cylinder engine has four spark plugs, six has six, and eight has eight. 

What Are The Best Plugs?

There actually is no right or wrong answer here but the best rule of thumb to follow is OEM. OEM means the original equipment that came with the engine. Each engine when it’s manufactured is built around a specific oil and spark plug.

During the time of assembly your engine is fitted with specific motor oil and specific spark plugs. Certain metrics like the thread count, gap, and materials used all take a core part in how healthy your engine runs.

As an example, my Cobalt is a 4 cylinder engine. During the manufacturing process it came with AC Delco Iridium spark plugs gapped at .32. Additionally it came with 5w-30 Mobil 1 Advanced Full Sythentic motor oil.

This would mean for my engine to run at peak performance I would want to stay as close to original equipment as possible. By reinstalling the same plugs, at the same gap and same specs. I know that the engine will run like a champion cause everything is within factory specifications.

So long story short, don’t be cheap, go with the original equipment.

What Type Should I Run?

How Many Spark Plugs Do I Need

The Red Wires In This Picture Are Spark Plug Wires!

As a follow up to the question above. OEM is of course still the best answer. However sometimes vehicles come with different plugs made from a different material. Sometimes you will have copper plugs, iridium plugs, platinum plugs, etc…

You should always try to stick with OEM but sometimes aftermarket parts kick in and you may need to switch. Different plugs and materials have different heat ratings and firing sequences. If you cannot stick with stock, take the best upgrade available for your vehicle.

Make sure you always stick with the same plug cap and never over tighten your spark plugs. This can lead to engine failure prematurely.

Miss firing Car? Tune It Up!

I don’t actually mean go and get a Dyno Tune either. More on that later. Typically when your car miss fires it’s due to a tune up being needed. A tune up in our book means fresh oil, fresh coolant, new plugs/spark plug wires, new filters, and new ignition coils.

Being that we are on the discussion of spark plugs, lets look at those first. You typically can always verify what cylinder is miss firing if your car throws a check engine light. Using a scan tool, pull the codes from the vehicle. If you have multiple random miss fires, replace each plug.

If you only have one miss firing cylinder, you should still change all the plugs.

Each spark plug fires and each one should be firing correctly, in order, at the correct temps.

Are My Plugs Good?

There’s only one way to find out! Take them out and take a peak at them. Spark plugs shouldn’t be burnt, corroded, or stripped. Using the image chart below, this will give you a good idea on what went wrong.

How Many Spark Plugs Do I Need

Common Spark Plug Conditions

This will help you identify how your engine is running and the steps you may need to take to keep it running in excellent condition. Take note of the image above and compare your spark plugs to these current ones.

How Many Spark Plugs Do I Need – Removing.

Removing spark plugs is actually quite simple. While we’re not going to specify how to do it on each and every single vehicle, this will help you across the board. Remember if you can do it on one vehicle, you can do it on them all!

You will always want to disconnect power to the battery before performing any repairs.

Most of the time you will need to remove your ignition coils/spark plug wires first. Get them out of the way until you can see down each cylinder. Once inside, grab a spark plug socket.

The spark plug socket contains a rubber washer inside, this helps grab the spark plug without damaging it during install or removal.

With everything now out of the way, you can now move onto removing the old spark plugs. Take each one out and compare it the chart above. If any of them have failed it is best to just replace all four.

Older Engines!

Many of our current generation vehicles are naturally aspirated with fuel injection. However back in the day we used to have older engines that ran directly off of spark plug wires with a distributor cap and rotor.

Replacing the plugs on these engines is super simple. Find the distributor cap which will look like a giant piece of plastic with many wires coming off of it. If you have a 4 cylinder, there will be 4 wires and 4 plugs. A 6 cylinder will have 6 wires with 6 plugs, and so on and so forth.

Follow the wires to your spark plugs and remove them just as we told you to do before. Inspect each plug and it’s conditions to get a good idea on how your engine is running.

Long Story Short…

So long story short, how many spark plugs do I need? You actually need the same amount as the size of your engine. If you have 4 cylinders, 4 spark plugs. If you have 6 cylinders, you will need 6 spark plugs.

This process keeps repeating all the way to whatever size your engine is. Hopefully this guide has helped you out! Be sure to check out our cv shaft symptoms guide!