What size socket to remove oil plug?
The correct socket size for the oil drain plug varies by vehicle; there is no universal standard. The two most common external-hex sizes are 14 mm and 17 mm, but you may encounter 12 mm, 13 mm, or 19 mm heads, and some plugs use an internal hex (Allen) or Torx bit. Always verify with your owner’s manual or by inspecting the plug head.
Why the size varies
Oil drain plugs are designed to match the engine’s drain pan and oil filter assembly, and manufacturers use different head styles and dimensions. The result is a range of possible socket or bit sizes. In addition to the head size, some plugs are tightened to specific torque specs, so using the wrong tool can damage the plug or pan.
Common sizes you might encounter
Before listing the most likely sizes, note that the correct option depends on the plug’s head type (external hex, internal hex, or Torx). The sizes below reflect what you’re most likely to find on modern cars. Use the corresponding tool that matches the plug head.
- 14 mm external hex head – the most common size for many cars and motorcycles.
- 17 mm external hex head – found on a number of American and some European models.
- 12 mm external hex head – less common, seen on certain compact or older vehicles.
- 13 mm external hex head – rarer, but present on specific makes and models.
- 19 mm external hex head – encountered on some trucks and larger engines.
- 6 mm Allen (internal hex) – some plugs require an internal hex key rather than an external hex socket.
- 8 mm Allen (internal hex) – another common internal-hex size on certain engines.
- Torx head (T40–T50 range) – a minority of plugs use a Torx pattern.
If your plug doesn’t match any of these sizes, consult the vehicle’s service manual or a dealership. Relying on a guess can strip the head or cause leaks.
How to confirm the correct size for your vehicle
Plug-head identification
Identify whether the drain plug has an external hex head, an internal hex (Allen) hole, or a Torx pattern. This determines which tool to use.
- External hex heads require a socket in the matching across-flats size (e.g., 14 mm, 17 mm, 12 mm, etc.).
- Internal hex plugs require a corresponding Allen key (e.g., 6 mm or 8 mm).
- Torx-pattern plugs require a Torx bit (e.g., T40 or T50).
Matching the head type to the correct tool helps prevent damage and speeds up the process.
Safe testing to confirm fit
If you’re unsure, proceed carefully to confirm the correct size without forcing a misfit. Use a progressive approach to avoid rounding off the head.
- Start with the most common sizes for external hex heads (14 mm and 17 mm) and test gently for a clean engagement.
- Do not apply full torque if the tool binds or slips; stop and reassess.
- For internal hex or Torx, ensure the bit is fully seated before applying torque.
Following these steps reduces the risk of damage and helps you identify the right size more quickly.
Practical tips to avoid damage
While removing and reinstalling the oil drain plug, keep these safety tips in mind to prevent damage to the plug, the oil pan, or the threads.
- Use the correctly sized socket or bit—using the wrong size is the fastest way to strip the head.
- If the plug is stubborn, apply penetrating oil and allow it to soak before attempting again.
- Consider a breaker bar for extra leverage on tight plugs, but avoid an impact wrench unless specified by the manufacturer.
- Wipe away oil around the plug area beforehand to prevent contamination when reinstalling and to help observe any leaks.
With the proper tool and technique, removing and reinstalling the oil drain plug can be done safely and efficiently.
Summary
There is no single socket size to remove every oil drain plug. The most common external sizes are 14 mm and 17 mm, with others (12 mm, 13 mm, 19 mm) appearing on some models, plus internal-hex (6 mm or 8 mm) and Torx options on rarer designs. Always verify by checking the owner’s manual, inspecting the plug head, or consulting a professional to avoid damage and ensure proper torque during reinstallation.
What tool do you use to remove a drain plug?
OTC Tools 5911A Drain Plug Pro Magnetic Remover, Black, 1/4 Inch Square Drive.
What size is the most common oil plug?
Most cars use oil drain plugs between 13mm and 17mm, depending on the brand.
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.
How to loosen a tight oil drain plug?
And then I'm back on it again with the standard socket. The whole vehicle about to flip off the lift. That is how tight that drain plug is. So you see it can't be stuck if it's liquid.
