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What size socket wrench for oil plug?

The correct socket size depends on your car’s drain plug hex head. Most cars use 14 mm or 17 mm, but there are exceptions. Always verify from the owner’s manual or by inspecting the plug head before choosing a socket.


Common drain plug head sizes


These are the sizes you’re most likely to encounter on routine oil changes. Sizes listed in millimeters cover metric plugs; some older or American models use common imperial (inch) sizes as well.



  • 12 mm

  • 14 mm

  • 17 mm

  • 19 mm

  • 3/8 inch (wrench size; roughly 9.5 mm across flats)

  • 7/16 inch (roughly 11.3 mm across flats)

  • 1/2 inch (roughly 12.7 mm across flats)

  • 13/16 inch (roughly 20.6 mm across flats) – less common, found on some older or heavy-duty models


Note: The exact size varies by vehicle. Start with the most common options (14 mm or 17 mm) and switch to others only if the fit is loose or won’t engage.


How to identify the correct size for your car


Use these steps to determine the exact size without risking damage to the plug or oil pan.



  1. Check the vehicle’s owner manual or service manual for the drain plug specification by model and year.

  2. Inspect the plug head and compare its hex shape to standard socket sizes. If in doubt, try a snug-fitting socket starting with 14 mm and 17 mm; apply a small amount of lubricant to help seating and avoid rounding.

  3. If you cannot determine the size by sight, bring the plug or the oil pan drain plug to an auto parts store; staff can identify the correct size by fitting sockets with you.

  4. Once you have the right size, use a properly sized socket (6-point is preferred) and follow the manufacturer’s torque specification to prevent leaks or stripping.


Having the exact size on hand reduces time during maintenance and protects the plug and pan from damage during removal and reinstallation.


Why this matters


Using the wrong size can strip the hex, damage the drain plug, or cause oil leaks. A correct, snug fit ensures a clean removal and reliable seal when you refill the engine oil.


Summary


Oil drain plug socket sizes are not universal. The most common are 14 mm and 17 mm, with occasional plugs in 12 mm, 19 mm, or imperial sizes like 3/8", 7/16", 1/2", or 13/16". Always verify by checking the owner’s manual or inspecting the plug head, and use the appropriate socket and torque spec for a safe, leak-free oil change. Keeping a note of your vehicle’s exact size can speed future maintenance.

What size socket do I need for an oil plug?


What size wrench to use for an oil drain plug depends on the size of the oil drain plug itself, which is a long bolt head. There is no universal oil plug size, but they do come in just a few several standard sizes, such as ¼ inch (. 6 centimeters), 3/8 inch (. 9 centimeters), ½ inch (1.3 centimeters), etc.



What tool should you use to loosen the oil pan drain plug?


The AGS Accu-Fit® Magnetic Drain Plug Removal Tool - the ultimate solution for hassle-free oil changes. This innovative tool is a must-have for anyone who wants to avoid the risks of getting burned by hot oil while changing their oil.



What size is the most common oil plug?


Most cars use oil drain plugs between 13mm and 17mm, depending on the brand.



Which is bigger, 1/2 or 3/8 wrench?


Size and Weight
The 1/2 inch drive makes the 1/2 impact wrench bigger and heavier. You get more power, but you might find it harder to use in small spaces. If you work in a garage or shop, the extra weight is not a big problem. For jobs that need you to move around a lot, the 3/8 impact wrench is easier to carry.


Kevin's Auto

Kevin Bennett

Company Owner

Kevin Bennet is the founder and owner of Kevin's Autos, a leading automotive service provider in Australia. With a deep commitment to customer satisfaction and years of industry expertise, Kevin uses his blog to answer the most common questions posed by his customers. From maintenance tips to troubleshooting advice, Kevin's articles are designed to empower drivers with the knowledge they need to keep their vehicles running smoothly and safely.