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How To Find The Right Spark Plug Socket Size (+4 FAQs)

January 18, 2022

What spark plug socket size should you use? 
And what type of spark plug socket is the best

In this article, we’ll help you find the right spark plug socket size for your car. We’ll also examine the types of spark plug sockets and answer a few related questions

This Article Contains: 

Let’s begin! 

How To Find The Right Spark Plug Socket Size

A spark plug socket is the right tool for handling spark plugs. 

It’s specifically designed to handle an old plug (or new plug in case of replacement) without damaging any spark plug wires or threads. 

You can usually invest in socket sets that contain the common size for spark plug sockets as well as other interchangeable sizes (so you always have the correct size at hand).

If not, spark plug sockets are individually available in different size varieties to match the spark plug, the most common size being the 5/8 inch size socket. Another common size is the 13/16 inch size socket. 

Here are some typical spark plug socket sizes: 

Socket Size
(in inches)
Socket Size
(in mm)
Typical Application 
5/8 16In a newer vehicle or small engine cars
13/16 20Older vehicle engines
9/1614Newer Asian cars and Ford vehicle engines
3/418Motorcycles
3/419Lawn mowers and small engine cars
7/822Aviation vehicles and tractors
11/1618Motorcycle engines, small engine BMW cars

You’ll need to pick a relevant spark plug socket depending on the size of your spark plug. 

Also, keep in mind the thread size of your spark plug threads. Spark plugs are available in two thread size options for motorcycles — 1/2 and 3/4 inches. For other vehicles, spark plug threads are also available in thread sizes like 8, 10, 12, 14, and 18 mm. 

So, make sure your new spark plug has similar threads as the old one because if you use the wrong thread size, your engine will be prone to misfires and carbon fouling.

Next, let’s look at the different types of socket sets available in the market. 

Types Of Spark Plug Sockets

Spark plug sockets are available in various extensions and interchangeable sizes. But their core component is usually manufactured in two styles. 

They are: 

A. Magnetic Spark Plug Socket

A magnetic spark plug socket consists of a small magnet inside a thin wall of the deep socket. 

This magnet will attach to the spark plug tip and prevent it from falling off whenever you remove a spark plug. This way, you don’t misplace your spark plugs during the process of removing them from your engine.

B. Rubber Grommet Spark Plug Socket

As the name suggests, a rubber grommet socket contains a rubber insert in the deep end of the spark plug socket. 

This is to secure the spark plug tip in place when removing an old plug. It prevents any bends or scratches and keeps the plug tips safe.

Now that we’ve gotten the basics on spark plug socket sizes and types, let’s look at some other related queries on spark plugs, and their answers.

4 Spark Plug FAQs

Here’s what you should know about spark plug sockets:

1. What Is A Spark Plug Socket?

A spark plug socket is very similar to a standard socket, except that it may also have a swivel extension bar to reach the spark plug hole without damaging other wires.

Like most other sockets, these are available in interchangeable sizes and can be attached to a torque wrench for better torque. However, spark plug sockets can handle more delicate repairs without damaging the equipment they’re working with. 

Some spark plugs are equipped with a magnet or a rubber grommet inside the socket.

2. How Does A Spark Plug Socket Work?

Spark plug sockets have a very similar function to that of a standard deep socket — to tighten or loosen a piece of equipment. 

To work, spark plug sockets attach to a turning tool with a square drive socket. They sometimes also have a hex or bi-hex head.

In short, you just fit the spark plug tip inside the socket head and then twist to loosen the spark plugs. 

The spark plug socket will work differently depending on the type of socket you’re using — whether it’s magnetic or has a rubber insert.

3. Do I Need A Special Socket For Spark Plugs? 

Yes and no. 
While a regular socket should do the job well too, a special socket is often the right tool for the job. 

Modern car engines have a very complicated spark plug placement. Some spark plugs are placed deep inside the engine, surrounded by spark plug threads and wires.

A regular socket can easily handle a basic spark plug replacement. But you’ll need the right socket size with swivel handles to reach the spark plugs without damaging the wires during changing. 

A universal joint socket may also do the job. Plus, a magnetic or rubber insert universal joint socket can better handle a new plug than regular socket sets. 

If you’re unsure, it’s best to take professional advice on the tools you should be using for your car.

4. How To Use A Spark Plug Socket? 

Here’s how you can use a universal joint or a regular socket to remove spark plugs: 

  1. Start by locating your spark plugs. Look for the distributor cap, coil pack, or ignition coil surrounded by plug wires. Trace these wires to the engine block, where it’s attached to spark plug sets.
  1. Remove each spark plug wire from the spark plugs. You may want to label your spark plug wires to know which one goes where. 
  1. Next, take your spark plug socket and fit it on the top of the spark plug. Ensure that it’s the right size. Ideally, it should fit snugly but not move around the plug. 
  1. Next, attach the socket wrench (or torque wrench, if you’re using one) to the back of the deep socket. You can also add an extension bar between the torque wrench and the socket. 
  1. All that’s left to do is rotate the wrench using the extension bar, and loosen the spark plug from the spark plug hole.

Note: When installing a new plug, you need to follow the same procedure and add dielectric grease on the spark boot. Dielectric grease prevents the new plug from sticking to the boot. Next, adjust the torque on the socket wrench according to the recommended torque spec, and you should be done!

Final Thoughts

A spark plug replacement is pretty straightforward for DIY repair enthusiasts. However, damaged or incorrectly sized spark plugs can cause problems with the engine that may cascade.

So, using the correct size and type for your spark plugs is very important, just like knowing if your engine uses a coil pack, coil-on-plug, or single ignition coil. 

Ideally, you should always err on the side of caution with your car repairs. Incorrect handling of spark plugs can cause misfires and engine failure. If you’re someone who isn’t confident about their mechanical skills, it’s best to leave the job to a mechanic. 

Why not give RepairSmith a try? 

RepairSmith is a mobile auto repair and maintenance solution with competitive, upfront pricing and a range of repair solutions. All repairs even come with a 12-month | 12,000 miles warranty.

Fill out this online form for a free cost estimate on your spark plug replacement.