What Spark Plugs Do, the Different Types, and More

This guide on spark plugs covers what spark plugs do in your car, the different types, and more.

What Spark Plugs Do

Internal combustion engines create combustion by igniting fuel. The spark plugs ignite the fuel by an electric spark. They sit in the engine cylinder and depending on the model can be connected to parts like ignition coils and spark plug wires.

The Different Types of Spark Plugs

Copper, Platinum, and Iridium

There are different types of spark plugs so it’s important to buy the right ones for your vehicle. If your engine has a beveled area, you’ll want spark plugs that have a beveled design. This also applies to an engine with a flat area in the engine cylinder, which will need spark plugs with a coinciding flat design.

Spark plugs can also differ in length and the gap size at the end of the plug, and installing the wrong spark plug could be detrimental to the engine.

Spark plugs can be made of metals like copper, platinum, and iridium. Platinum spark plugs are more resistant to wear than copper plugs and will likely last longer. Copper plugs will usually last between 20,000 and 30,000 miles. Platinum plugs will usually last around 60,000 to 100,000 miles.

Iridium spark plugs have a more controlled spark to avoid issues like the spark jumping around. Iridium spark plugs can last to around 120,000 miles.

Tips for Installing New Spark Plugs

Purchase Manufacturer Recommended Spark Plugs

Spark plugs can also have different electrodes and heat ranges. You want to make sure the new spark plugs are the same electrodes that the manufacturer recommended. This means if your vehicle manufacturer specifies platinum spark plugs, those are what need to be installed.

Torque the Spark Plugs to Manufacturer Specification and Replace Them at Recommended Intervals

Make sure to torque the spark plugs to manufacturer specification and try not to remove them before the next service interval. Check the owner’s manual for the recommended service interval and the spark plug gap.

More torque wrench tips

Use Spark Plug Tools

You can adjust the spark plug gap with a spark plug gap tool but often the spark plugs won’t need to be gapped and sometimes can damage them.

You’ll need a spark plug socket to remove the spark plug. The spark plug socket has a rubber grommet to grip the spark plug so you can securely remove it.

You can apply dielectric grease to the end of the ignition coil for coil-over-plug types. This will improve the seal.

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