Searching for
Spark Plugs

Spark Plugs

Choose the Make of Your Vehicle

Spark Plugs at 1A Auto

What are Spark Plugs and where are they Located?

Spark plugs are a relatively simple, but integral part of your car or truck’s ignition system. Located in each cylinder head, the spark plugs carry high voltage electricity into the cylinder to create a spark that ignites the compressed air-fuel mixture, and the resulting combustion is what ultimately powers your automobile. They also act to transfer heat away from the combustion chamber to the engine’s cooling system.

The spark plug receives power, which is initially generated by the vehicle’s battery when a vehicle is started, either directly from a distributor or from an ignition coil depending on the type of ignition system used in the vehicle, via a spark plug wire which connects to the spark plug terminal (or connector) found at the top of the plug. In newer vehicles that have coil-on-plug setups, wires are not used, as each cylinder has its own coil, which is usually bolted to the valve cover on top of each spark plug, that transfer the current directly to the plug through a coil boot. The charge then travels through a central, metal conductor (or core) which is covered by a ceramic insulator. At the end is a small electrode connected to the metal shell that grounds into the engine block when the bottom half of the spark plug is threaded into the cylinder head. The core’s tip, which protrudes out the bottom of the ceramic insulator into the combustion chamber, also acts as an electrode, called the center electrode. Electricity arcs across a gap between the two electrodes, creating the spark that ignites the air-fuel mixture that's been compressed by the piston, which is required to make the engine run.

The spark plugs and wires are arranged according to the engine cylinders' correct firing order sequence. Current is transferred to each spark plug wire according to this specific sequence, allowing for proper ignition spark at just the right time for the engine to start and the vehicle to move. Proper spark plug functioning is essential to proper ignition.

The number of spark plugs found in a car or truck varies depending on the engine in the vehicle. There are also different types of spark plugs available. A standard plug has a copper center electrode core which is surrounded by a nickel alloy, seen at the end of the plug. There are also premium spark plugs available, which make use of precious metal such as platinum or iridium, rather than the nickel alloy.

How do I Know if my Spark Plug Needs to be Replaced?

Due to their location in the cylinder head, spark plugs are exposed to extremely high temperatures and forces as well as other effects of combustion. They are, of course, designed to withstand these pressures, but can be expected to eventually wear down. The time this takes will vary from one spark plug to another, but 20,000 to 30,000 miles is a common lifespan for copper plugs. Performance plugs made of different metals like platinum or iridium can last much longer. 

Since a bad spark plug will effect ignition in its cylinder, it will often result in poor engine performance. This may manifest as rough idling, hesitation or surging during acceleration, a pinging or knocking noise coming from the engine, engine misfires, or worst of all, a complete failure to start the engine. 

It may be possible to identify the source of your problem by visually inspecting the spark plug. This may point to a deeper problem that has caused your spark plug failure. It is typical to find the end of the plug has turned a light brown color, but sooty or ashy carbon deposits can be a sign of an overly rich fuel-air mixture. Melted electrodes can signify that pre-ignition is occurring, combusting the fuel too early. A cracked ceramic insulator indicates engine overheating or fuel detonation (knocking). Mechanical damage to the spark plug might mean that it was installed improperly or there is some sort of foreign material in the cylinder. 

Can I Replace a Spark Plug Myself?

Considering the limited life of a spark plug, it’s fortunate that replacing them is relatively easy on most engines. They are found in the cylinder head on top of the engine block which means that they are often easy to access. You may have to remove an engine cover to reach them. In some cases, such as front wheel drive V6 engines, they may be harder to reach and you may have to remove parts of the air intake system or other parts to access them. 

There are a couple steps you can take to ensure that your spark plug replacement goes smoothly. The spark plugs have a specific firing order that must be maintained for the engine to work properly. For this reason, it is best to replace the spark plugs one at a time or to label the spark plug wires with tape and a marker to ensure they are replaced in the correct order. Before installing the new spark plugs, you will need to consult your owner’s manual to determine the correct torque to tighten the spark plug hex nut to in order to avoid damaging it, and the correct gap between the electrodes so that they spark properly. In order to measure that gap you will need a tool known as a spark plug gapper. Applying anti-seize grease to the threads will help you more easily remove the spark plugs next time you replace them, but be sure not to get the grease on the electrodes as it may make them fail to fire. 

Need a Spark Plug Replacement?

To put it simply, a failed spark plug will result poor engine performance, which can manifest in a variety of ways including the inability to start it. Of course, being unable to start your engine means your car or truck isn’t going anywhere. Therefore, making sure you replace your spark plugs as required, and as soon as possible if they have failed, is critical to proper vehicle operation. Luckily, 1A Auto has that “spark” that you need. We carry aftermarket spark plugs, including performance spark plugs made of iridium or platinum metal, for many makes and models, and at great prices.

At 1A Auto, we make shopping for replacement spark plugs for your car, truck, SUV or van easy - we're here to help you select the right part for your vehicle! Call our customer service toll free at 888-844-3393 if you have any questions about our aftermarket spark plugs, warranty, compatibility or to purchase, or you can buy online.

Over 3,000

Watch the 1A Auto Videos
We're here to help


hablamos español: 866-401-3393

1A Auto Parts

Customer Feedback

Customer Feedback
"Thanks for the fast reliable service. Great price, and the headlights were as good as oem or better!!! Keep up the good work..."
- Dwuan M.
Read More
Free Shipping!


hablamos Español:866-401-3393
For Orders Placed By 5pm Est