What Size Socket Fits an Oil Pan Drain Bolt?

Most oil pan drain bolts use a 13 mm, 14 mm, 15 mm, or 17 mm socket, but the exact size depends on the make and model: many American vehicles use 13 or 15 mm; Toyota and Nissan commonly use 14 mm; Honda and Subaru often use 17 mm; older VW/Audi models may use 19 mm; and some European cars use an internal 8 mm hex (Allen) or Torx. Because there’s no universal standard, confirm your vehicle’s spec in the owner’s manual—or test-fit the socket—to avoid rounding the bolt or over-tightening.

Why There Isn’t One “Correct” Socket Size

Oil drain plugs vary by manufacturer, engine family, and even by model year. The “socket size” refers to the bolt head size, not the thread size. While metric hex heads dominate, some vehicles use internal hex (Allen) or Torx designs, and a few late-model cars and trucks use twist-lock plastic plugs that don’t require a socket at all. Knowing your vehicle’s specific hardware is key to a clean, damage-free oil change.

Common Socket Sizes by Automaker

The following list summarizes typical socket sizes for oil pan drain bolts across popular brands. Use it as a starting point; always verify for your exact year/engine.

• Ford, GM, Chrysler/Dodge/Jeep/Ram: 13 mm or 15 mm hex head (many trucks: 15 mm)
• Toyota/Lexus: 14 mm hex head (common with M12 or M14 plugs)
• Nissan/Infiniti: 14 mm hex head (some models may vary)
• Honda/Acura: 17 mm hex head (widely used across models)
• Subaru: 17 mm hex head (common on FB/FA and EJ engines)
• Hyundai/Kia: 17 mm or 14 mm hex head depending on engine
• Volkswagen/Audi: 19 mm hex head on many older steel pans; newer models often use plastic or internal drive plugs (see special cases)
• BMW/MINI: 17 mm hex or 8 mm internal hex (Allen), depending on engine; some use replaceable aluminum crush washers
• Mercedes-Benz: 13–17 mm hex or internal hex (Allen), varies by engine family
• Mazda: 14 mm or 17 mm hex head, model-dependent

These patterns cover a large share of vehicles on the road, but running changes and engine-specific designs mean outliers exist. Confirming the spec prevents damage and saves time.

Special Cases and Notable Exceptions

Some vehicles deviate from the standard external hex drain bolt. Be alert for the following designs that affect the socket you’ll need—or whether you need a socket at all.

• Internal hex (Allen): Common sizes include 8 mm (e.g., many BMW/MINI and some Mercedes engines)
• Torx/internal drive: Some European models use Torx (often T45–T50) or triple-square designs
• Plastic twist-lock plugs: Certain late-model Ford and VW/Audi applications use a tool-free or specialty plastic plug that twists in/out; replacements are often single-use
• Aftermarket pans/plugs: Magnetic or oversize repair plugs may use different head sizes than OEM
• Skid plates and undertrays: You may need additional socket sizes or bits (10 mm, T25/T30, etc.) just to access the pan

If your plug looks unusual or plastic, avoid forcing a hex socket: verify the required tool and replacement part to prevent leaks or breakage.

How to Identify the Correct Size Quickly

When in doubt, a quick check can pinpoint the right tool and reduce the risk of rounding the bolt head.

1. Consult your owner’s manual or factory service information for the drain plug specification.
2. Visually inspect the plug: external hex, internal hex (Allen), Torx, or plastic twist-lock.
3. Test-fit a 6-point socket starting near the common sizes for your brand (e.g., 14 mm for Toyota, 17 mm for Honda/Subaru, 13/15 mm for Ford/GM/Chrysler).
4. Ensure a snug, no-slop fit; avoid 12-point sockets on stubborn plugs to reduce rounding risk.
5. If internal drive, try an appropriately sized Allen (often 8 mm) or Torx bit (T45–T50).
6. Confirm torque spec and crush washer type before reinstallation.

Taking a minute to verify the tool and spec reduces the chance of stripping threads, cracking a pan, or causing a slow leak.

Torque, Washers, and Best Practices

Typical Torque Ranges

Passenger-car drain plugs are commonly tightened to about 25–30 ft-lb (34–41 N·m). Many Honda and Toyota engines specify roughly 27–30 ft-lb; some trucks specify closer to 30–40 ft-lb. Aluminum pans may require the lower end of the range. Always use the manufacturer’s specification.

Crush Washers and Sealing Rings

Many vehicles use a replace-once crush washer (aluminum or copper), commonly for M12 or M14 plugs. Reusing worn washers can cause drips. Keep a few spares matched to your plug size and thread pitch.

Avoiding Damage

Use a quality 6-point socket, break loose with steady pressure, and retighten with a torque wrench. If the plug feels cross-threaded or won’t seat by hand, stop and inspect. For plastic plugs, follow the exact removal/installation procedure and replace if specified as single-use.

Recommended Tools and Supplies

Having the right gear on hand makes the job cleaner and safer, especially when encountering different plug designs.

• Socket set including 13, 14, 15, 17, and 19 mm 6-point sockets
• 8 mm Allen key/socket and Torx bits (T45–T50) for internal-drive plugs
• Torque wrench capable of 20–50 ft-lb
• New crush washer matched to your plug (M12 or M14 common)
• Drain pan, gloves, rags, and proper undertray fastener tools

Preparedness prevents mid-job delays and helps ensure a leak-free result once the engine is back up to temperature.

Bottom Line

There is no single socket size for oil pan drain bolts. The most common are 13, 14, 15, and 17 mm external hex, with brand tendencies as noted, plus some internal 8 mm Allen or Torx designs and a few plastic, tool-free plugs. Confirm your vehicle’s specification, use a snug 6-point socket, replace the crush washer, and torque to the manufacturer’s value to avoid leaks or damage.

Summary

Oil drain plug socket size varies by vehicle. Expect 13 or 15 mm on many American models, 14 mm on Toyota/Nissan, 17 mm on Honda/Subaru, and 19 mm or internal-drive (8 mm Allen/Torx) on some European cars. Always verify the exact size and torque in your manual, use a 6-point socket for removal, replace the crush washer, and follow proper torque to ensure a clean, reliable oil change.

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 is the oil drain bolt?

Mild Steel M12 (12 mm) Oil Drain Bolt, Size: 15 mm.

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.

What size socket do I need for the oil pan bolt?

You will need to determine the specific socket size for your vehicle by checking your car’s make, model, and year, but common sizes for oil pan bolts include 15mm, 16mm, and 9/16-inch, so it’s best to measure the bolt head or consult your owner’s manual. Using a 6-point socket provides a better fit than an 8-point socket, reducing the risk of rounding off the bolt.
 
How to find the right socket size:

1. Check the Bolt Head: Inspect the bolt head for its size. 
2. Look at Your Owner’s Manual: Consult your vehicle’s owner’s manual to find the specific size for the oil drain plug. 
3. Measure the Bolt: If you can’t find a size, use a measuring tool to get the exact dimensions. 
4. Research Online: Look up the specific year, make, and model of your car to find what size socket is needed for the oil pan bolt. 

General tips for oil pan bolts:

• Use a 6-point socket: A 6-point socket has more surface area than an 8-point socket, which gives a more secure fit and prevents the bolt head from being stripped. 
• Use a quality socket: A high-quality, well-fitting socket is essential to avoid damaging the bolt. 
• Consider the bolt type: Some oil drain bolts have a non-standard or flared shape that may prevent a standard socket from seating properly, making it more difficult to use.