How to Replace Spark Plugs — Beginner’s Guide

Quick: how often do you need to replace your car’s spark plugs? If you don’t have your car’s manual in front of you, you probably won’t know this one off the top of your head. The answer can be anywhere from 30,000 to 100,000 miles, but individual vehicles can vary. And specific types of spark plugs can have longer or shorter lifespans.

How to Change Your Spark Plugs

If you change them yourself to save money, you’ll have to gather the right tools and prepare your car for the job.

The Tools

Here’s what you need:

• Socket set and socket wrench
• Spark plug gapper
• Spark plug socket
• Spark plug wire pliers
• Socket wrench extender
• Torque wrench
• Safety goggles
• Gloves
• Shop towels
• Vacuum
• Colored tape
• Electrical tape
• Microfiber towels

Notice the safety items on this list, and use them. Otherwise, you risk pinched fingers, burns, and other injuries.

The Parts

Ideally, all you’ll need is a new set of spark plugs. Make sure to get plugs that are appropriate for your vehicle. Not every spark plug will fit every engine. Reference your owner’s manual, which assumes that you don’t need spark plug wires.

You might also need anti-seize lube if the spark plugs are hard to remove. When buying new spark plugs, try to get a set that has anti-seize properties so you don’t have to use anti-seize lube in the future.

Setting Up Your Car

Park on a dry, level surface and let your car cool down. The engine will be hot after running, and you don’t want to touch it unless it’s had time to dissipate that heat. Then, disconnect the negative post of the battery and clean the engine area with your vacuum to keep from exposing your new spark plugs to dust and dirt. You may want to wrap the unplugged terminal in electrical tape to ensure it doesn’t touch an errant tool and create a short circuit.

Removing the Plug Wires

Not all cars make it easy on you to remove the plugs and wires. If you need to remove other parts first, do so. Once you have access, carefully remove the plug wires from the plugs using your spark plug wire pliers. If you’re replacing the wires, don’t worry if you accidentally damage the old ones. Simply label the wires with colored tape to maintain the right order.

Removing the Plugs

Using your plug socket and socket wrench, remove the spark plugs. Inspect them to ensure there’s no damage indicating other engine issues. They should be slightly darkened, but there should not be any built-up carbon, gas, or oil. The center electrode should not be bent or damaged.

Installing New Plugs

Use your spark plug gapper to make sure the gap between the center and ground electrodes is correct. After that, thread the plugs into the engine by hand, making sure there’s no excessive resistance. If there is, take it out and try again. You don’t want to cross-thread the plugs.

Using your torque wrench, tighten the plugs with the factory-spec amount of torque and then reattach the plug wires and the battery after that. Once that’s done, congratulations are in order: you’ve successfully replaced your spark plugs.