What Size Socket Is an Oil Pan Drain Plug?

There isn’t a single universal size for oil drain plugs. Most passenger cars use a 13 mm, 14 mm, 15 mm, or 17 mm hex socket; some trucks and European models may require 19 mm–24 mm, while a minority use an internal hex (Allen, commonly 6 mm–10 mm), Torx-style, or a square-drive recess. Always confirm with your owner’s manual or measure before turning the wrench.

Why There’s No One-Size-Fits-All Socket

Automakers choose drain plug designs based on engine layout, oil pan material (steel vs. aluminum vs. plastic), and regional standards (metric vs. SAE). Over time, manufacturers have also shifted from traditional external hex plugs to internal hex or specialty plastic plugs on some newer engines. The result: the “right” socket varies by brand, model, engine, and even model year.

Common Socket Types and Sizes You’re Likely to Encounter

While there’s no universal fit, the following sizes cover the majority of everyday oil changes. These are typical, not guaranteed; always verify your specific vehicle.

• 13 mm: Common on many GM/Chevrolet cars, some Ford models, and various compacts.
• 14 mm: Very common on Toyota/Lexus, Nissan/Infiniti, and many Mazda models.
• 15 mm: Seen on many Ford and GM vehicles, including some trucks/SUVs.
• 17 mm: Frequent on Honda/Acura, Subaru, and many Hyundai/Kia applications.
• 19 mm: Found on some European models and larger or older plugs.
• 21–24 mm: Occasionally on larger trucks, some diesels, and specialty applications.
• Internal hex (Allen): Often 6 mm, 8 mm, or 10 mm on certain European and newer aluminum/plastic pans.
• Square-drive recess: Some plugs accept a 3/8″ or 1/2″ ratchet drive directly (no socket).
• Torx-style/specialty plastic plugs: Present on a few newer plastic pans—check service info for exact bit and one-time-use requirements.

If you stock a few common metric sockets (13–19 mm), an Allen set (6–10 mm), and standard ratchet drives, you can cover most situations. But a quick measurement or manual check remains the safest route.

Quick Ways to Identify the Correct Size Without Guesswork

Before you reach for a tool and risk rounding the plug head, take a minute to identify what you need. These steps help you nail the size and style on the first try.

1. Consult your owner’s manual or factory service manual for the drain plug size and torque spec.
2. Measure the plug head across flats with a caliper or use a socket gauge; compare to common metric sizes.
3. Test-fit a six-point socket (not twelve-point) starting with the snugger option to prevent rounding.
4. Check if the plug is internal hex, Torx-style, or has a square recess; match with the correct bit or ratchet drive.
5. Look for aftermarket drain valves (e.g., Fumoto); they often require a different size or just a lever flip.

A proper identification takes moments and can save you from a stripped plug or damaged oil pan—especially on aluminum or plastic pans.

Typical Torque Specs and Washer Tips

Using the right torque and washer matters as much as the socket size. Over-tightening is a common cause of stripped threads and leaks.

• General torque range: Many drain plugs fall between 20–30 lb-ft (27–40 Nm) on smaller plugs/pans; larger plugs may spec 30–40 lb-ft (40–54 Nm). Always follow the exact spec for your engine.
• Crush washers: Many vehicles use a replaceable aluminum or copper crush washer; replace it at every oil change to prevent seepage.
• One-time-use plugs: Some modern plastic plugs (and a few metal ones) are designed for single use. Replace them rather than reusing.
• Material matters: Aluminum and plastic pans typically require lower torque than steel to avoid damage.

If you don’t have the official spec, err on the lower end of typical ranges, confirm sealing, and never force a plug that doesn’t thread smoothly by hand first.

Brand Cheat Sheet (Typical, Not Universal)

These brand patterns are common in workshops but vary by engine and year. Use them as a starting point, not a substitute for verification.

• Toyota/Lexus: Often 14 mm external hex.
• Honda/Acura: Frequently 17 mm external hex.
• Nissan/Infiniti: Commonly 14 mm external hex.
• Mazda: Often 14 mm external hex.
• Subaru: Frequently 17 mm external hex.
• Hyundai/Kia: Commonly 17 mm (some 14 mm).
• Ford: Often 13 mm or 15 mm; some use internal hex or square-drive plugs.
• GM/Chevrolet/GMC: Typically 13 mm or 15 mm.
• Volkswagen/Audi: Mix of 19 mm external hex and 6–8 mm internal hex; some newer plastic pans use specialty plugs.
• BMW/MINI: Older engines often 17 mm external; many newer aluminum/plastic pans use 8 mm internal hex or specialty plugs.
• Mercedes-Benz: Commonly 13–14 mm external or 8 mm internal hex; some models favor top-side oil extraction.
• Jeep/Ram/Chrysler: Often 13 mm or 15 mm depending on engine family.

Because exceptions are common—especially with engine options—double-check your specific model and engine code before loosening the plug.

Tools Worth Having on Hand

A small set of the right tools prevents delays and damage during an oil change.

• Six-point metric socket set (13–19 mm) and 3/8″ and 1/2″ drive ratchets.
• Allen (hex) bit sockets (6, 8, 10 mm) and a Torx bit set for specialty plugs.
• Torque wrench matched to your vehicle’s spec.
• New crush washer or replacement drain plug, if specified.
• Drain pan, gloves, rags, and brake cleaner for cleanup.

With these basics, you’ll be equipped for most drain plug designs you encounter.

Summary

There is no universal oil drain plug socket size. Most cars use 13 mm, 14 mm, 15 mm, or 17 mm; some trucks or European models run larger (19–24 mm), and a minority use internal hex, Torx-style, or square-drive plugs. Verify your exact size and torque spec in the manual, use a six-point socket, and replace the crush washer to ensure a leak-free oil change.

Are all oil pan drain plugs the same size?

No, not all oil drain plugs are the same size; they vary by vehicle make, model, and year, and even by the specific design of the oil pan. To ensure a proper fit and prevent leaks or damage, you must find the correct drain plug for your vehicle, which can be done by checking the owner’s manual or using an online parts lookup tool. 
Why drain plugs aren’t universal:

• Varying designs: Opens in new tabAuto manufacturers design their vehicles differently, resulting in different oil pans and, consequently, different drain plugs. 
• Thread size: Opens in new tabThe “size” of a drain plug is determined by its bolt diameter and thread pitch (the distance between the threads), for example, M14x1.5. 
• Material and features: Opens in new tabDrain plugs and their associated gaskets also come in different materials (like aluminum, copper, or rubber) to ensure a good seal with the specific oil pan. 

How to find the right drain plug:

1. Consult your owner’s manual: Opens in new tabThis is the best source for the exact specifications of the original equipment (OE) drain plug. 
2. Use a parts lookup tool: Opens in new tabMany auto parts stores and online resources offer a parts lookup service where you can enter your vehicle’s information to find the correct part. 
3. Match the OE plug: Opens in new tabWhen replacing a drain plug, it is best to choose one with the same quality, style, design, and fitment as the original. 

Consequences of using the wrong size: 

• Leaks: An incorrect plug can fail to create a proper seal, leading to oil leaks.
• Damage: A plug that doesn’t fit correctly can damage the oil drain pan’s threads or not seal properly.

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

Play. So let’s go ahead open it up really quick. Yeah we’re going to use some tin snips why. Not cuts right through. There. And there we go just a little flexible dongle deal thingy.

What size socket for oil pan plug?

Place a 3/8-inch (0.9 centimeters) socket in the socket wrench, fit it over the drain plug’s nut and turn it counterclockwise. The oil drain plug should open easily, draining the used oil from the engine. Make sure to place a bucket and some newspaper under the car’s engine to catch all the draining oil.

What socket size do I need for an oil change?

You need a socket wrench (14mm or 15mm), an oil filter wrench, an oil drain pan, a funnel, and a new oil filter.