Spark Plug Socket Sizes (w/ Chart)

Spark plugs are a vital part of any combustion motor, and they’re also one that will wear out in time. While a normal deep well socket can technically be used to remove spent plugs, there’s a good chance you’ll damage good plugs. 

A spark plug socket is the better option.

Keep reading to learn what the two most common spark plug sizes are as well as additional sizes that you may encounter whether it be a car, truck, motorcycle, lawnmower or other small engine.

See Also: How to Check Your Spark Plugs (Step-by-Step)

What Is a Spark Plug Socket and How Does It Work?

Spark plug sockets are designed specifically to handle spark plugs. They have two possible interiors, both of which are designed to carefully hold the plug without damaging it.

Magnetic sockets use magnets to hold the plug, while rubber inset sockets create a soft rubber cradle for the plug to sit in.

While this doesn’t sound like anything special when compared to a deep socket, it really can make a difference. The specialized bed helps prevent slippage during work, which in turn makes installation and removal faster.

For many models of car where spark plugs are seated deep within the engine block, this could mean a whole lot of time saved or busted knuckles. Additionally, there’s far less risk of damaging the insulation when using a spark plug socket.

Spark Plug Socket Sizes

There are only a handful of spark plug sockets available, both as deep and regular. Deeps sockets will work much better when dealing with a recessed plug. 

Additionally, most sockets will fit a standard 3/8” drive and kits may even include one or more extensions or swivels. It’s usually best to aim for thin walls, as these can get into deep recesses easier no matter what socket size.

The most common spark plug sizes are 5/8″ and 13/16″ but the actual size you need is very vehicle dependent. Spark plug sockets are usually sold individually (Gearwrench example) but also come in sets. Some include various sizes and extensions, such as this higher end set by Sunex.

Please note that 7/8” sockets are rarely included in socket sets due to their more specialized use and require a 1/2” drive.

While 12-point versions of many sockets are available (sets often include a 12-point for 14mm plugs), the 6-point option tends to be much more common. Only a few vehicles, such as some newer BMW engines, use 12-point plugs.

See Also: 6pt vs 12pt Sockets

Spark Plug Socket Sizes Chart

Note: It’s rare that a particular engine manufacturer sticks with a single spark plug size across all its products. The chart simply provides common use applications. It’s recommended to do a Google search for the year, manufacturer, and type of engine you have to get the most accurate results. For example, “2020 Mazda 2.5L spark plug size”.

• Author
• Recent Posts

Mark Stevens

Owner at Car Treatments

Mark is a veteran auto technician who has honed his skills with over 19 years of service working at various independent shops. While Fords and Mazdas are his specialty, he enjoys working on practically any vehicle (except a Nissan 300ZX).

He’s known for his attention to detail and problem-solving skills and enjoys coming up with out-of-the box solutions when the situation requires it.

When he's not troubleshooting customers' cars, you'll most likely find him working on his current project ('96 Bronco) or cooking Italian food for his family.

Latest posts by Mark Stevens (see all)

• Replace the Engine or Replace the Car? (11 Factors to Consider) - Apr 11, 2024
• Plastic Piece Dragging Under Your Car? (What It Is and What To Do) - Mar 21, 2024
• Timing Belt vs Timing Chain (What’s the Difference?) - Feb 27, 2024