Spark plugs are a critical component of a combustion engine that will eventually wear out. While it is technically possible to remove wasted plugs using a standard deep well socket, there is a good possibility you may harm good ones. When working on a car, truck, motorcycle, or lawnmower, you can always use a spark plug socket.
Almost every spark plug is available in a size of HEX sizes. Hex refers to the socket or diameter in the middle of a spark plug used to spin, screw-down, or unscrew the spark plug.
In our guide, you can learn all you need to know about any spark plug size you encounter, from little engines to huge automobiles listed on our spark plug socket size chart, where you can see additional sizes in use.
By the conclusion, you’ll understand spark plug wrench sizes and be able to utilize our simple spark plug sizes chart to determine which size plug should be installed in which type of engine. (Read Is There A Difference Between Star And Torx)
What are the common spark plug socket sizes?
What’s the most common size of spark plug socket? You’ll discover there is no standard size spark plug socket size in your plug socket set. The most common sizes, 13/16′′ and 5/8′′ are sometimes confused with standard spark plug socket sizes.
Although a 3/4” plug socket is common in lawnmowers, these sizes are mainly found in cars. As a result, common formats are available; however, they vary depending on the vehicle.
Finding the proper spark plug socket size is not difficult, but many individuals make a mistake. To find the size of the spark plug socket, follow the procedures below.
- To begin, check your manual to find the kind and model of the pre-gapped plug. This makes determining the socket size simple.
- Check the size of the socket on the spark plug itself. If you have access to it, you can measure the hex size with Vernier calipers.
Here you can find the concise spark plug socket size chart that shows most plug sizes in use and answers the vehicles on which they are used.
You will notice no direct spark plug socket sizes mm that relate to spark plug socket size metric. (Read Allen Key Sizes In mm)
You have both on a different vehicle; you will need to check which your vehicle has or have in your kit, so you won’t forget you have a socket or need to convert mm to metric.
| Spark Plug Size | Application |
|---|---|
| 14mm | Newer European and Asian vehicles as well as some motorcycles |
| 9/16" | Ford |
| 5/8" | Newer vehicles from GMC, Nissan, Chevy, Subaru. Small engines from Briggs & Stratton, Koehler etc. |
| 11/16" | Older BMW vehicles |
| 18mm | Most motorcycles, and some small engines |
| 3/4" | Lawnmowers, small engines, and older GM vehicles |
| 13/16" | Older large engine vehicles |
| 7/8" | Aviation, tractors, and older vehicles |
It is worth noting here you should use a torque wrench with your spark plug when installing the spark plug. A torque wrench tool can stop you from over-tightening the plug and stripping the cylinder head thread.
A socket wrench of this type should fit various sockets, or there will be an adapter so the tool can fit assorted sizes. (Find the Best Complete Socket Set)
What are the 3 spark plug socket sizes?
Only a few deep and regular spark plug sockets are available. Deep sockets function far better when dealing with a recessed plug. Universal joints are articulated joints that allow you to rotate the wrench around one axis while rotating the reliable hexagon sockets along another axis.
Spark plug sockets are typically supplied individually but sets with assorted sizes and extensions are also available. 7/8″ sockets are rarely provided in socket sets because of their unique purpose and length and require a 1/2″ drive.
Although there are 12-point versions of several sockets, the 6-point version is significantly more common. Only a few automobiles, such as some newer BMW engines, use 12-point plugs.
Are spark plugs all the same size?
Spark plug sockets are specifically designed to hold spark plugs. They come with two interiors, both of which hold the plug securely without damaging it.
Rubber inset sockets, for example, produce a soft rubber cradle for the plug to sit in, whereas magnetic sockets employ magnets to hold the plug insulator in place.
While this may not seem like much compared to the varied sizes of the deep socket, it can make a significant difference. The unique bed prevents sliding during work, making installation and removal go more quickly.
This can save lots of time and save a few bashed knuckles where spark plugs are situated deep within the engine block, where you may also need an extension on some cars. Employing a spark plug socket reduces the danger of damaging the insulation. (Read Metric To Sae Conversion)
Sizes of Spark Plug Sockets
There are only a few deep and normal spark plug socket set variations available. When dealing with a recessed plug, deep sockets will work better in a complex automotive engine such as a BMW.
Most sockets accept a standard 3/8” drive, and some kits can contain one or more extensions or swivels. Thin walls are preferable because they allow easier access to deep depths.
Is there a special spark plug socket?
There are two sizes of spark plugs: 5/8 inch and 13/16 inch. The rubber insert in most spark plug sockets keeps the plug tightly in place.
Torque wrenches have a gauge that shows how much torque is applied when the wrench is turned. A universal joint may be useful if you can’t fit a wrench and extension in the space surrounding your spark plug.
A set of boot pliers, a clean rag, some rubbing alcohol, a tube of anti-seize, and compressed air or a wet/dry vacuum should all be on hand as well.
Spark plug sockets are specifically designed to attach to spark plugs without damaging them, unlike standard socket wrenches. Magnetic sockets hold the plug in place via magnets and rubber inset sockets. (Read Light Bulb Base Size Chart)
This means there is a lower chance of damaging the spark plugs insulation in the car’s engine block. Spark plugs have a unique bed that prevents the plug from slipping in the socket. This allows for the installation and maintenance of engine parts to be completed in a shorter time.
This will make an enormous difference to car owners in many cars whose spark plugs are buried deep into the engine block. They are less concerned about damaging any portion of the car, such as stripping threads or dropping the plug because of the spark plug size.
