What size socket is my oil drain plug?

Socket size for an oil drain plug isn’t universal. In most modern cars, you’ll typically need a 14 mm or 17 mm hex socket, but some vehicles use 12 mm, 13 mm, or even larger sizes like 19 mm. The exact size depends on your specific make, model, and year, so it’s best to verify with the owner’s manual or measure the plug head directly.

This article explains how to identify the correct size for your vehicle, lists common drain-plug head sizes you may encounter, and offers practical steps to determine the exact socket size without damaging the plug or threads. It also covers what to do if you can’t confidently identify the size from appearance alone.

Common drain plug socket sizes

The following sizes cover the most common hex heads you’ll encounter on oil drain plugs for passenger cars and light trucks.

• 14 mm — The most widespread size for many Japanese, Korean, American, and several other makes. A 14 mm socket will fit a large portion of cars you’ll see on the road.


• 17 mm — Frequently used on many European makes (such as some VW/Audi/BMW/Mercedes models) and a noticeable number of other vehicles.


• 12 mm and 13 mm — Found on a subset of older or specialized models; less common today but worth checking if your plug head looks small.


• 19 mm — Occasionally used on some trucks and heavier-duty applications.


• SAE sizes like 1/2 inch or 9/16 inch — Some older American-market vehicles may use these non-metric head sizes.

When in doubt, begin with the most common sizes (14 mm and 17 mm) and test carefully to avoid rounding the plug. If the head feels rounded or slips, stop and reassess rather than forcing a larger size.

Head patterns and tool types

Oil drain plugs come with slightly different head designs. Most use a standard hex (6-point) or a 12-point head, both of which can be driven by a socket of the appropriate size. Some plugs require a specific socket type (deep-wall, impact-rated, or 6-point vs. 12-point) to fit properly and avoid slippage. Always use the correct socket style for your plug to minimize the risk of rounding the head, which can complicate removal during service.

In addition, some plugs include a washer or sealing ring. If you replace the drain plug, use the manufacturer’s recommended washer and torque specification to ensure a proper seal and prevent leaks.

How to determine your exact size

To confirm the correct socket size for your car’s oil drain plug, follow these steps.

1. Check the owner’s manual or a service manual for the recommended drain plug size or torque spec for your vehicle.


2. Inspect the drain plug head visually. If you can’t identify the size by eye, measure the distance across the flat surfaces with a caliper or ruler, or try a plug-size gauge if you have one.


3. Start with the most common sizes (14 mm or 17 mm) and test fit carefully. If the plug won’t seat or rounds, stop and try the other size rather than forcing a fit.


4. If the head is damaged, stripped, or you can’t remove the plug safely, stop and seek professional assistance to avoid damaging the oil pan threads or the plug bore.

Following these steps helps ensure you identify the right socket size without risking damage to the plug or engine components.

What to do if you can’t determine the size confidently

When you’re unsure or the plug is damaged, take a cautious approach:

• Consult a certified mechanic or a dealership service department for the exact spec for your vehicle, especially if it’s a specialty or European model.


• Bring the vehicle’s year, make, model, and engine type to assist in locating the precise drain plug size and torque spec.


• If you must proceed yourself, avoid forcing a socket onto a plug head and consider replacing the drain plug and washer if you’ve encountered wear or damage.

Professional confirmation can prevent cross-threading, stripping, or leaks that could lead to costly repairs later.

Summary

In short, there isn’t a single universal socket size for an oil drain plug. Most modern cars use 14 mm or 17 mm hex heads, with occasional plugs in 12 mm, 13 mm, 19 mm, or SAE sizes. Always verify with your owner’s manual or by carefully measuring the plug head. Use the correct socket type, follow the manufacturer’s torque spec, and replace any worn washers to ensure a proper seal and a trouble-free oil change. If you’re unsure, consult a professional to avoid damage to the plug, threads, or pan.

How do I know what size my oil drain plug is?

There is no single oil drain plug size, as it varies by vehicle. Common sizes are expressed in a thread size format like M12x1.75cap M 12 x 1.75𝑀12𝑥1.75 or M14−1.50cap M 14 minus 1.50𝑀14−1.50, and a corresponding wrench or socket size like 15mm15 m m15𝑚𝑚 or 18mm18 m m18𝑚𝑚. The best way to find your car's specific plug size is to check the owner's manual, measure the plug directly, or look up the parts for your vehicle's make and model.
 
Common sizes

• M12×1.75cap M 12 cross 1.75𝑀12×1.75: Often paired with a 15mm15 m m15𝑚𝑚 wrench head. 
• M14×1.50cap M 14 cross 1.50𝑀14×1.50: A common size, sometimes with a different head size. 
• M16×1.50cap M 16 cross 1.50𝑀16×1.50: Also found on some vehicles, typically with a 17mm17 m m17𝑚𝑚 head. 

How to find your specific size

1. Check your owner's manual: This is the most reliable source for your vehicle's specifications. 
2. Look up parts: Many auto parts websites have a lookup tool where you can enter your car's information to find the correct plug. 
3. Measure the existing plug:
   • Thread size: You can use a thread pitch gauge to measure the distance between threads (in millimeters or threads per inch). 
   • Head size: Measure the diameter of the head that the wrench fits onto. 
4. Consult the plug itself: Some replacement plugs may have the size stamped on them, but this is not always the case. 

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What size socket for an oil drain plug?

The correct socket size for an oil plug depends on your car's make and model, as there is no single universal size. Common metric sizes include 14mm, 15mm, 17mm, and 19mm, while some older vehicles may use SAE sizes like 3/8" or 1/2". Always inspect the plug to confirm the size, as using the wrong socket can damage the bolt head. 
You can watch this video to learn how to change the oil in a Honda CR-V, including removing the drain plug: 1m1A Auto: Repair Tips & Secrets Only Mechanics KnowYouTube · Aug 13, 2018
How to find the right size

• Check your owner's manual: This is the most reliable way to find the correct size for your specific vehicle. 
• Inspect the plug: Visually examine the drain plug to determine its size. You can also measure it with a caliper if needed. 
• Try common sizes: If you can't find your manual, start with common metric sizes like 14mm, 15mm, 17mm, or 19mm. 
• Use the right socket type: A 6-point socket is recommended over a 12-point socket to prevent stripping the bolt head. 

This video demonstrates how to use a drain plug removal tool with a magnetic feature: 52sScavenger1320YouTube · Feb 23, 2024
Important tips

• Use the correct socket: A well-fitting socket is crucial to avoid rounding the bolt head. 
• Tighten properly: Do not overtighten the drain plug, as this can strip the threads. Tighten it to the manufacturer's specifications, or just snug it up if you don't have a torque wrench. 
• Replace the crush washer: It is a good practice to replace the crush washer on the drain plug to ensure a proper seal. 

What size is the most common oil plug?

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

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.