The Tools Needed To Change Spark Plugs

Few other projects provide a more immediate benefit than replacing old, damaged, or ineffective spark plugs. After all, your vehicle’s spark plugs are essential for its overall performance. Whether you are tackling your first or 101st spark plug project, you need the right tools to change them effectively. When you need tools, there’s no better place to go than your local AutoZone.

When To Change Your Vehicle’s Spark Plugs

Whether you are an automotive enthusiast or just prefer to avoid car trouble, occasionally replacing spark plugs is part of regular maintenance. Put simply, if you ignore your car’s plugs, you are asking for trouble.

Spark plug manufacturers design their products both to be durable and have a long life. You may not need to worry about your vehicle’s spark plugs for 30,000 miles or more. Still, you should not forget to replace your spark plugs when the time comes.

An old, damaged, or ineffective spark plug may cause your vehicle’s engine to misfire. Alternatively, old plugs can cause the emissions from your engine to increase. Even worse, a bad spark plug can leave you stranded somewhere you would rather not be.

How to Tell if Your Spark Plugs are Bad

If any of the following applies to your vehicle, it may be time for a change:

  • Your owner’s manual recommends changing spark plugs
  • Your car’s engine misfires
  • Your check engine light illuminates
  • Your car has difficulty starting
  • Your car accelerates slowly
  • Your car’s engine idles roughly

Learn more about bad spark plug symptoms.

While other problems and maintenance issues can cause the above situations to occur, spark plugs are often to blame. If changing your vehicle’s spark plugs does not remedy your vehicle’s engine problems, you may need to do some troubleshooting. Still, swapping out bad spark plugs often fixes issues with your vehicle’s overall performance.

How To Choose the Right Spark Plug Tools

On most vehicles, replacing spark plugs is not a difficult project. In fact, you can likely do the job in just a couple hours on the weekend. Nevertheless, you need the right tools to replace spark plugs correctly. While you may run into problems, the following tools are often essential for achieving professional-grade results.

1. Your vehicle’s owner’s manual

Before you can replace spark plugs, you need to know where to find them and how to access them. Your vehicle’s owner’s manual is an excellent resource. If the manual does not shed sufficient light on the subject, you may want to invest in a vehicle-specific aftermarket manual. Chilton and Haynes have some excellent manuals that give you a step-by-step guide to locating and replacing spark plugs as well as a list of tools to replace spark plugs.

2. A spark plug socket

To remove spark plugs, you need a spark plug removal tool that grabs and twists the spark plugs inside your vehicle’s engine. Because spark plugs can be in awkward positions, you may also need an extension for your spark plug socket. Choosing one that locks in place may help you avoid the sort of aggravation that occasionally accompanies a spark plug replacement.

3. A wobble socket

If a standard socket does not work, choosing a wobble socket may be a better idea. Wobble sockets are often essential equipment for removing iridium spark plugs. The wobble socket is also smaller than traditional spark plug sockets, allowing you to access tight spaces easier. If a regular socket simply does not fit into the confined area in which you must work, trying a wobble socket may be a better approach.

4. Spark plug boot puller pliers

Occasionally, spark plug boots fuse with your vehicle’s plugs. If this is the case, you do not want to pull on the wires themselves. Doing so may damage the wires, potentially rendering them unusable after your spark plug replacement. Instead, use spark plug boot puller pliers to gently work boots free.

5. A flexible handle ratchet

Sometimes you must be a bit creative to remove spark plugs. If your vehicle’s engine configuration requires you to work in tight or bizarre places, using a flexible handle ratchet allows you to remove spark plugs without standing on your head. Using one in conjunction with a wobble socket may be the perfect solution for removing your vehicle’s spark plugs from areas where space is a premium.

6. A torque wrench

When replacing spark plugs, how much you tighten each plug matters. If you do not tighten plugs sufficiently, you risk a bad connection. Too much tightening, though, can destroy both your spark plugs and your engine. Therefore, use a torque wrench and manufacturer specifications to tighten each spark plug appropriately.

7. A spark plug gap gauge

Your new spark plugs need the correct gap to function optimally. Rather than estimating gap, use a spark plug gap gauge to space your new plugs perfectly. To correctly use the gap gauge, first consult manufacturer recommendations. Then, place the gauge between the plug’s center and its electrodes, lining it up to meet manufacturer specifications.

Other Things You May Need

While these items are not necessary to every spark plug replacement, they
can certainly help:

  • Anti-Seize Lubricant: If your plugs were really hard to remove, it might be because the previous installer didn’t use an anti-seize product. When you apply this product to the spark plugs before installing them, you reduce the risk of having plugs fuse to engine parts. When using an anti-seize product, though, you likely need to reduce the torque by up to 10% on each plug.
  • Spark Plug Wires: You may be able to reuse your existing spark plug wires after replacing old, damaged or ineffective plugs. Still, your plug wires are essential components. If you notice signs of wear and tear or other damage, replacing spark plug wires when you add new spark plugs is a good idea.
  • Distributor Cap: This part only applies to vehicles that have distributors. Just as spark plugs and wires can wear out over time, your vehicle’s distributor cap may not last forever. After replacing spark plugs and wires, inspect the distributor cap for signs of damage. If you see any, opt for a new distributor cap.

Achieving Success

Replacing bad spark plugs is probably a project you can tackle on a weekend. Before you do, though, you must be sure you have the tools needed to change spark plugs. With a bit of planning and the correct tools, you can achieve success.

If the job is too big for you, seek out one of our Preferred Shops to help you do the job.

Advice, how-to guides, and car care information featured on and AutoZone Advice & How-To’s are presented as helpful resources for general maintenance and automotive repairs from a general perspective only and should be used at your own risk. Information is accurate and true to the best of AutoZone’s knowledge, however, there may be omissions, errors or mistakes.

Be sure to consult your owner’s manual, a repair guide, an AutoZoner at a store near you, or a licensed, professional mechanic for vehicle-specific repair information. Refer to the service manual for specific diagnostic, repair and tool information for your particular vehicle. Always chock your wheels prior to lifting a vehicle. Always disconnect the negative battery cable before servicing an electrical application on the vehicle to protect its electrical circuits in the event that a wire is accidentally pierced or grounded. Use caution when working with automotive batteries. Sulfuric acid is caustic and can burn clothing and skin or cause blindness. Always wear gloves and safety glasses and other personal protection equipment, and work in a well-ventilated area. Should electrolyte get on your body or clothing, neutralize it immediately with a solution of baking soda and water. Do not wear ties or loose clothing when working on your vehicle.

FREE Loan-A-Tool® program requires returnable deposit. Please note that the tool that you receive after placing an online order may be in a used but operable condition due to the nature of the Loan-A-Tool® program.

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