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What Size is a Spark Plug Socket Spanner Or Wrench


This guide will reveal the size of spark plug sockets, spanners, and wrenches. Spark plugs supply engines with air and fuel, which power their operation. To be able to change them, they must first be removed from their socket. Knowing the size is key to safely removing and installing engine plugs.

Spark plug sockets have hex cavities that define their size. The size of the socket will depend on the make and model of the vehicle. Common sizes for spark plug sockets are 3/8″ and 1/2″ drives, and sizes range from 14mm to 18mm (9/16″ to 3/4″). Specialty and larger sizes can be up to 21mm or 0.825″ and 24mm or 0.960″, but these are usually only needed for heavy-duty vehicles, like commercial trucks. If you’re unsure which size is suitable, check your owner’s manual for exact information and go for a universal spark plug socket set, which usually covers all common sizes.

Types of Spark Plug Sockets

Spark plugs need changing? There’s a few types of sockets that can help. Spark plug sockets, spanner sockets and combination wrenches – each has their own benefits and can be used for different things. Let’s look at the different types so you can pick the one which fits your needs best.

  • Spark plug sockets are designed to fit the hexagonal shape of spark plugs.
  • Spanner sockets are designed to fit the square-shaped nuts of spark plugs.
  • Combination wrenches are designed to fit the hexagonal shape and square shape of spark plugs.

Standard Sockets

Standard spark plug sockets are popular. They are made from chrome vanadium steel, which is hardened and tempered for strength and durability. The sockets have a shallow inner part for simple access to spark plugs. Sizes range from 6–8mm, 13/16”–1-3/16”, and 10-18mm.

Adaptor sets and “swivel heads”, that make hard-to-reach spark plugs easier, also come in standard configurations.

Deep Sockets

Deep sockets are tailored to spark plug applications. They come in different sizes and shapes. The special design allows them to reach areas where standard sockets cannot. Also, they lessen the risk of damage to the spark plug, by using more of the plug head’s surface and spreading the pressure out.

To figure out which deep socket to use, take a look at the markings on the spark plug or check the vehicle manufacturer’s guidelines.

Common sizes for deep sockets include:

  • 5/8
  • 13/16
  • ¾-inch
  • 19mm 1-inch
  • 21mm 1-1/8 inch (9/16)
  • 22mm 1-3/8 inch (3/4)

Certain spark plugs may need other sizes such as 14mm or 15mm.

Aside from conventional type sockets, hex type sockets, flexible extensions, swivel head swiveling ratchet adapters and specialty ratchets can be used in tight or hard-to-reach locations.

Magnetic Sockets

Magnetic spark plug sockets are designed to catch spark plug debris. Magnets help pull out shards from old plugs, which could damage an engine. They are usually made of chrome-plated steel for strength. Variations range from 5/8” – 3/4” (+6mm). They provide a secure grip on any size of spark plug. Rubber inserts keep a firm grip and prevent slipping. Some have a swivel head for easier access in tight places.

Swivel Sockets

Swivel sockets are designed for a range of spark plugs. The tapered ends, called tangs, enable the sockets to fit tight curves. These tangs are angled to stop the socket and spark plug from breaking due to tight turns.

Swivel sockets come in sizes from 5/8” to 18mm and have a double-ended design. Perfect for areas with limited space, these sockets can be found in auto or specialty tools types. Make sure to pick the right size swivel socket to prevent any possible damage by a tool that doesn’t fit.

Universal Sockets

Universal spark plug sockets come in handy. They fit into different spark plug sizes, so you can use one tool for many tasks. They have a special shape for gripping and fitting spark plugs. The internals of them let them fit even in hard-to-reach places.

Three main sizes exist – 6mm, 8mm, and 10mm. This lets you precisely fit your spark plug type. They also feature a deepwell design. This allows you to securely remove and install plugs in awkward and tight positions. Some sockets even have a rubber O-ring. This helps them maintain grip and prevents slipping or dropping.

Plus, varieties exist in both metric and imperial measurements. So, you can use them for all types of uncommon measurements. Universal sockets are great investments. They give you the adaptability needed for DIY servicing operations. Such as changing out old, worn, or damaged spark plugs. No need to buy various tools for each job.

Types of Spark Plug Wrenches

Spark plug wrenches come in four sizes: 8mm, 10mm, 12mm, and 14mm. Each size is designed to fit the spark plug it’s used with. Let’s explore the different types:

  • 8mm spark plug wrench
  • 10mm spark plug wrench
  • 12mm spark plug wrench
  • 14mm spark plug wrench

Standard Wrenches

Steel is the material of choice for standard spark plug wrenches. They have a single, curved U-slot. This gives great contact with the spark plug. It also has a 90-degree angle to make it easier to turn. These wrenches are perfect for leaded, non automotive and regular applications. Metric and SAE sizes are both available. Make sure you know your bike’s needs before buying.

12-point versions are an option too. This type has 12 points that spread the pressure on the spark plug. Easier removal without damage is the result. Longer versions may also be available. These give extra leverage when needed in hard-to-reach places.

Flexible Wrenches

Flexible spark plug wrenches are made for mechanics to access spark plugs easily in tight spots, like motorcycles and small engines. They have a smooth finish aluminium shaft that won’t harm the spark plug thread when rotating.

These wrenches are bendable, so they can get to plugs in places other tools can’t reach. There are two types: socket-style and hexagonal-style. Socket-style has more grip but needs a special adapter for tiny plugs. Hexagonal-style have 6 sides, but sometimes need accessories for certain tasks.

Flexible wrenches are of top quality and come in various lengths, from 3 inches to 24 inches. They also vary in size and shape, and come with different ends for extra grip. Perfect for many projects!

Ratcheting Wrenches

Ratcheting spark plug wrenches are tools specifically for removing and installing spark plugs. They are convenient because you don’t have to unscrew the plug from the socket. You can turn the wrench a few degrees and easily remove it.

There is a wide selection of sizes, from 6mm to 24mm. Some models work with both standard and magnetic spark plugs. They come with adapters that fit different types of plugs. They are available in metric and imperial sizes, so check what size you need before buying.

Ratcheting wrenches give you high torque power with little effort, making them useful in any toolkit.

Offset Wrenches

Offset wrenches are mainly used on older spark plug models. They are bent, L-shaped for access in tight spaces. The offset head allows for a long handle and fits different sizes of spark plugs. This design holds the spark plug tightly and is not great for replacing or removing multiple plugs in one go.

Certain models have adjustable wrenches which can offer more flexibility and maneuverability.

Types of Spark Plug Spanners

Spark plug spanners exist in all shapes and sizes. They come in various types for different car needs. We’re gonna explore the different kinds and which size fits your car best. So, let’s take a look!

  • Standard spark plug spanners are the most common and are used for most cars.
  • Offset spark plug spanners are used for cars with limited access to the spark plug.
  • Flexible spark plug spanners are used for cars with hard-to-reach spark plugs.
  • Universal spark plug spanners are used for cars with multiple spark plug sizes.

Standard Spanners

Standard spark plug spanners, also named wrenches, sockets or spanners, are metal tools. They are designed to fit around the hexagonal part of the spark plug. These spanners come in different sizes, from 9mm to 16mm, they can be single-ended or double-ended. The selection depends on the size of the hexagonal portion of the spark plug.

They are excellent options for both amateurs and professionals. They provide consistent removal or installation of spark plugs. The range of sizes makes them suitable for many types of vehicles, such as cars, trucks, vans and motorcycles.

It is essential to choose a spanner that fits correctly over the hexagonal portion of the spark plug. This ensures safety during use.

Adjustable Spanners

Adjustable spanners, also known as crescent wrenches, are a common tool. They come in a variety of sizes and can be used for any spark plug job. The head has one jaw that can be adjusted. It is attached to a handle for extra leverage. These spanners are perfect for spark plug changes. They work with both metric and SAE nuts and bolts.

  • Select the right size spanner for the bolt.
  • Make sure it fits snugly around the head of the spark plug or bolt.

Combination Spanners

Combination spanners are great for removing spark plugs. They have a conical shape that fits the spark plug housing. You can buy them in metric or imperial sizes. Steel or aluminium are the most common materials.

These spanners work at home or professionally. They fit in tight places and grip without damaging delicate parts. Plus, they have other uses too, like a wrench or spanner.


Spark plugs are vital for a vehicle’s engine to work properly. To take out or put in a spark plug, you’ll need the correct size tool. Socket sizes may differ from 5/8 of an inch to 13/16. A spanner can range between 5/8 of an inch and 7/8, while a wrench may vary from 3/4 of an inch to 1 and one quarter inches. Pick the right size to avoid harm to the spark plug threads or incorrect torque when tightening.

Before trying to fix anything, be sure to look in your car manual to find out which size socket, spanner or wrench is suggested for your particular make and model!

Frequently Asked Questions

Q: What size is a spark plug socket?

A: The size of a spark plug socket is usually either 5/8 inch or 13/16 inch.

Q: What size is a spanner or wrench?

A: The size of a spanner or wrench depends on the size of the spark plug socket. Generally, a spanner or wrench of 7/8 inch or 15/16 inch will fit a 5/8 inch spark plug socket, while a spanner or wrench of 1 inch or 1 1/16 inch will fit a 13/16 inch spark plug socket.

Q: Is there a universal size for spark plug sockets, spanners or wrenches?

A: No, there is no universal size for spark plug sockets, spanners or wrenches. Different spark plug sockets, spanners or wrenches may be needed depending on the size of the spark plug socket.

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