What size socket do I need to remove an oil pan plug?

There isn’t one universal size. Most passenger cars use a metric socket between 13 mm and 19 mm—14 mm and 17 mm are especially common—while many domestic vehicles use 13 mm or 15 mm. Some engines require an internal hex (Allen) bit, a Torx bit, or even a quarter‑turn plastic plug. Check your owner’s manual or measure the plug to confirm before you turn a wrench.

Why there’s no single size

Oil drain plugs vary by manufacturer, engine family, model year, and even by the type of oil pan used (steel vs. aluminum). European makes often favor larger heads or internal hex bits; many Asian brands standardize around 14 mm or 17 mm; U.S. brands commonly use 13 mm or 15 mm. Heavy‑duty trucks can use larger sizes. Because of these differences—and because some plugs are single‑use or plastic—verification is essential.

Common sizes by brand (typical, not guaranteed)

The following list outlines sizes you’re likely to encounter by brand. Use it as a practical starting point if you don’t have the manual handy, but always verify on your specific vehicle.

• Toyota/Lexus: usually 14 mm external hex
• Honda/Acura: often 17 mm external hex
• Nissan/Infiniti: commonly 14 mm external hex
• Subaru: usually 17 mm external hex
• Hyundai/Kia: often 17 mm external hex
• Mazda: commonly 17 mm external hex
• Ford: often 13 mm external hex; some models use a plastic quarter‑turn plug
• GM/Chevrolet/GMC: frequently 15 mm external hex
• Chrysler/Dodge/Jeep/Ram: often 13 mm or 15 mm external hex
• Volkswagen/Audi: 19 mm external hex or 6–8 mm internal hex; many use single‑use aluminum plugs
• BMW/MINI: 17 mm external hex or 8 mm internal hex on many models; some use single‑use plugs
• Mercedes‑Benz: commonly 13–14 mm external hex or 8 mm internal hex (varies widely by engine)
• Heavy‑duty trucks/diesels: can be larger (19–24 mm, 3/4″–1″); verify by engine code

Use these norms as guidance only. Even within a brand, engine generations differ, and aftermarket pans or plugs can change the required tool.

Identify your plug type before choosing a tool

Not every oil drain plug is a standard bolt head. A quick look underneath will tell you what tool you need and help you avoid rounding the plug.

• External hex bolt head: uses a standard socket (most common)
• Internal hex (Allen): typically 6 mm or 8 mm bit (some European/aftermarket pans)
• Torx/star: less common for engine oil drains; verify size before use
• Plastic quarter‑turn: found on some newer models; releases with tabs/special tool, not a socket

Matching the tool to the plug style prevents damage and makes removal safer and cleaner.

How to choose and use the right socket

Use the steps below to select the correct size and remove the plug without damage.

1. Confirm size: check the owner’s manual/service manual or measure the bolt head across the flats with a caliper. If testing by feel, choose the tightest fit—no wiggle.
2. Use a 6‑point socket: it grips better than a 12‑point and reduces the risk of rounding, especially on shallow heads.
3. Select the right drive: a 3/8″ drive ratchet handles most plugs; use a short extension for clearance if needed.
4. Break loose with control: apply steady force; if tight, use a small breaker bar rather than an impact. Turn counter‑clockwise to loosen.
5. Mind the washer: many plugs use a crush washer (aluminum or copper). Replace it every oil change to prevent leaks.
6. Torque on reinstallation: tighten to the spec in your manual. Many passenger cars fall in the roughly 20–35 lb‑ft (27–47 N·m) range, but specs vary.

Working methodically with the right tools prevents stripped plugs, cracked pans, and future leaks.

Torque and washer notes

Torque values and washer types vary by engine. As a broad guide, many steel or aluminum pans call for roughly 20–35 lb‑ft (27–47 N·m), but some engines specify less or more. Always follow the manual’s exact spec. Common washer sizes are associated with plug thread size (for example M14x1.5 plugs typically use an M14 crush washer). If your plug is labeled “single‑use,” replace it at every service.

If the plug is rounded or stuck

Don’t force a bad fit—there are safer ways to free a stubborn drain plug.

• Switch to a quality 6‑point socket or a dedicated bolt‑extractor socket for rounded heads.
• Apply penetrating oil and let it soak; tap the head lightly to help it wick in.
• Use a short breaker bar for controlled leverage; avoid impact guns on aluminum pans.
• For steel pans only, gentle localized heat can help; avoid heat near plastic pans or seals.
• Replace the plug and washer once removed; inspect threads in the pan for damage.

Patience and the correct extraction tool usually solve the problem without escalating to pan repair.

Quick kit to have on hand

Keeping a compact set of sizes and accessories covers most vehicles you’ll encounter.

• 6‑point metric sockets: 13 mm, 14 mm, 15 mm, 17 mm, 19 mm
• Hex (Allen) bits: 6 mm and 8 mm; Torx bits: T45/T50 for European oddballs
• 3/8″ drive ratchet, short extension, and small breaker bar
• Torque wrench capable of 15–50 lb‑ft (20–70 N·m)
• New crush washers and, where required, single‑use drain plugs
• Drain pan, rags, gloves, and eye protection

With these tools, you can identify and service most drain plugs confidently and cleanly.

Summary

There’s no single socket size for oil drain plugs. Most passenger vehicles use 13–19 mm sockets—14 mm or 17 mm are especially common—with domestic brands often at 13 mm or 15 mm; some engines need internal hex or Torx bits, and a few use plastic quarter‑turn plugs. Verify your plug type and size, use a snug 6‑point socket, replace the crush washer, and torque to the manufacturer’s spec to avoid leaks or damage.

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 size socket to remove oil drain plug?

There isn’t a single socket size for all oil plugs; the correct size depends on your vehicle’s make, model, and year. Common sizes include 17mm and 14mm for many Japanese and European cars, but you might need to check your vehicle’s specifications or visit an auto parts store for help. A 6-point socket is recommended for better grip to avoid stripping the bolt head. 
How to find the right socket size

1. Check your vehicle’s manual: The most reliable way is to consult your car’s owner’s manual to find the specific drain plug size. 
2. Identify the head type: Most drain plugs have a hex-shaped bolt head. 
3. Measure the bolt head: If you have a socket set, try a few sizes to see which one fits snugly. 
4. Consult an auto parts store: Bring the vehicle information to an auto parts store, and they can look up the specific size for you. 
5. Consider common sizes: While not universal, many Japanese and European cars use metric sizes, with 17mm and 14mm being common. 

Tips for changing the oil plug

• Use a 6-point socket: This type of socket is more effective at gripping the bolt and prevents the head from getting rounded off. 
• Use a 3/8-inch drive socket and ratchet: This is a common size for most DIY oil changes. 
• Have a replacement plug ready: If the old drain plug is worn or stripped, you’ll need a new one to replace it. 

What size is the bolt for the oil pan?

There is no universal size for an oil pan bolt; the correct size depends on the specific make and model of your vehicle, which can be a metric size (like M8, M12) or an imperial size (like 1/4-inch or 5/16-inch). To find the right size, you must consult your car’s owner’s manual or a vehicle-specific repair guide, or if replacing a bolt, use a proper-sized wrench or socket to remove the old one and match its specifications.
 
How to Determine the Correct Bolt Size

1. Check Your Vehicle’s Owner’s Manual: This is the most reliable way to find the exact bolt size and thread specification for your car. 
2. Use a Vehicle-Specific Repair Guide: Online resources or a printed manual for your car’s make and model will provide detailed specifications for all components. 
3. Examine the Old Bolt:
   • Metric Bolts: These will be labeled with an “M” followed by a number (e.g., M8, M12), with the number indicating the diameter. 
   • Imperial (SAE) Bolts: These will be specified with a fraction (e.g., 1/4-inch, 5/16-inch) indicating the diameter. 
4. Match the Wrench Size: If you can’t find the exact size, use a wrench that fits the bolt head snugly. A 15mm, 16mm, or 9/16-inch is common for some vehicles. 

Common Bolt Types and What They Mean

• Bolt Head Size: The size of the wrench needed to turn the bolt (e.g., 3/8 inch). 
• Thread Size: The diameter and pitch of the threads on the bolt. For example, a 5/16-18 bolt has a 5/16-inch diameter and 18 threads per inch. 
• M8 x 1.25 x 25: A common way to describe metric bolts. The “M” indicates it’s metric, “8” is the diameter in millimeters, “1.25” is the thread pitch, and “25” is the length in millimeters. 

Important Considerations

• Bolt Length: Opens in new tabNot all holes are the same depth, so always check the depth of the bolt holes to ensure you use the correct bolt length for each one. 
• Gaskets: Opens in new tabThe oil pan often uses a gasket to prevent leaks. Using the correct size bolt with the proper gasket is essential. 

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

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