What Size Bolt Is an Oil Pan Plug?

There isn’t one universal size: most modern cars use a metric oil drain plug, with M14×1.5 the most common. Other frequent sizes are M12×1.25, M12×1.5, M12×1.75, and M16×1.5; some older U.S. vehicles may use 1/2″-20 UNF. Always confirm the exact size for your engine via the owner’s manual, service documentation, or by checking the plug itself. In practice, the “right” size depends on the specific engine and oil pan design, which vary by brand, model year, and market.

Why There Isn’t a Single Standard

Oil drain plugs are engineered to match the oil pan’s material, wall thickness, and threaded bung. Automakers also standardize within engine families, not across entire brands. As aluminum pans became more common and manufacturing globalized, metric threads predominated, but variations in thread diameter and pitch remain. That’s why two cars from the same brand can have different plug sizes if they use different engines or pans.

The Sizes You’ll See Most Often

The list below highlights the oil drain plug thread sizes most frequently encountered on passenger vehicles and light trucks today, along with typical notes you’ll see in service literature. These are broad norms—not a substitute for the exact specification for your engine.

• M14 × 1.5 — The most common modern size; often paired with a 17 mm or 13–17 mm hex head and a 14 mm-ID crush washer. Typical torque range: about 25–30 lb-ft (34–40 Nm), but confirm per vehicle.
• M12 × 1.25 — Common on many Toyota/Lexus applications; usually uses a 12 mm-ID crush washer and a 14 mm hex head. Typical torque range: roughly 20–25 lb-ft (27–34 Nm).
• M12 × 1.5 — Seen on some Mazda, BMW, and other applications. Typical torque range: roughly 18–22 lb-ft (24–30 Nm).
• M12 × 1.75 — Appears on select engines and some motorcycles. Typical torque range: roughly 18–22 lb-ft (24–30 Nm).
• M16 × 1.5 — Common on Subaru and some trucks/SUVs; typically uses a 16 mm-ID washer. Typical torque range: about 30–36 lb-ft (40–49 Nm).
• M20 × 1.5 — Found on some heavy-duty/diesel applications. Typical torque range: roughly 35–45 lb-ft (47–61 Nm) or per OEM spec.
• 1/2″-20 UNF — Older domestic (U.S.) applications; less common on modern vehicles. Typical torque range: about 25–30 lb-ft (34–40 Nm).
• Plastic/composite drain plugs — Used on some newer BMW and VW/Audi pans; typically replaced at each service and use an O-ring seal rather than a crush washer. Torque is usually lower (often in the 15–30 Nm range), and exact OEM specs must be followed to avoid damage.

Head/hex size is not a reliable indicator of thread size or pitch, and torque varies with pan material and design. Always use the vehicle’s official specification when tightening the plug.

Examples by Brand (Not Exhaustive)

These brand-level patterns can help you narrow down possibilities, but exceptions exist—what matters most is the engine and pan used in your specific model and year.

• Honda/Acura: Frequently M14 × 1.5 with a 17 mm hex; uses a crush washer.
• Toyota/Lexus: Often M12 × 1.25 with a 14 mm hex; 12 mm-ID washer commonly specified.
• Nissan/Infiniti: Commonly M14 × 1.5 on many models.
• Subaru: Often M16 × 1.5 on late-model vehicles.
• Mazda: Frequently M14 × 1.5 on recent models; verify by engine.
• Hyundai/Kia: Often M14 × 1.5 on modern applications.
• Volkswagen/Audi: Commonly M14 × 1.5; some newer engines use replaceable plastic drain plugs with O-rings and specific torque procedures.
• BMW: Mix of M12 × 1.5 and M14 × 1.5 depending on engine; some plastic pans use single-use plastic plugs.
• Mercedes-Benz: Frequently M14 × 1.5 on many engines; verify by engine code.
• Ford: Mixed; many modern models use M14 × 1.5, while some older engines used 1/2″-20 UNF.
• GM/Chevrolet/GMC: Many use M14 × 1.5; heavy-duty trucks and diesels may be larger (e.g., M20 × 1.5).
• Chrysler/Dodge/Ram/Jeep: Often M14 × 1.5 on modern gasoline engines; verify per engine.
• Motorcycles/ATVs: Frequently M12 variants (e.g., M12 × 1.5), but highly variable—check the service manual.

Because brands share engines across models and years—and change designs over time—confirm by engine code or VIN rather than assuming a brand-wide standard.

How to Identify Your Plug Size Quickly

If you’re unsure of your vehicle’s drain plug size, these steps will help you determine it accurately and avoid damaging threads or over-tightening.

1. Check documentation: Look in the owner’s manual or the factory service manual for the drain plug spec and torque.
2. Use your VIN: Enter your VIN on an OEM parts site or at a dealer to pull the exact drain plug part number and size.
3. Measure the plug: With a digital caliper, measure the major thread diameter (mm). Use a thread pitch gauge to read the pitch (e.g., 1.25, 1.5).
4. Confirm with hardware: If needed, test-fit with known-thread nuts or a gauge to ensure both diameter and pitch match.
5. Match the washer: Replace the crush washer or O-ring with the correct size (ID must match the plug thread diameter).
6. Tighten to spec: Use a torque wrench and follow the exact torque for your engine and pan material; avoid sealants unless specified, and do not use thread tape.

Taking a few minutes to verify the exact size and torque spec prevents cross-threading, stripped pans, and leaks after the oil change.

Maintenance and Safety Notes

Getting the size right is only part of a clean, reliable oil change. These best practices help preserve the oil pan and ensure a proper seal.

• Replace the crush washer (aluminum or copper) every oil change unless your plug uses an O-ring that is designed to be reused or replaced per OEM guidance.
• Inspect threads on both plug and pan; repair damaged pan threads with a proper insert (e.g., Time-Sert) rather than oversized self-tapping plugs when possible.
• Be mindful of aluminum pans; they strip more easily than steel. Proper torque is critical.
• Magnetic plugs can help capture fine metal particles; just ensure the thread and length match the OEM spec.
• Do not rely on the hex size to identify the thread; metric and imperial hex heads can overlap, leading to incorrect assumptions.

Following OEM procedures and using the correct parts delivers a better seal, protects the pan, and reduces the risk of future leaks or repairs.

Summary

There’s no single “standard” oil pan drain plug size. M14×1.5 is the most common on modern vehicles, followed by M12 and M16 variants, while some older U.S. models use 1/2″-20. The only reliable answer for your car is in the official spec—confirm by manual, VIN, or precise measurement, use the correct washer, and torque to the specified value.

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

There is no universal oil pan socket size; the specific size depends on the vehicle’s year, make, and model, but common sizes include 15mm, 16mm, or 9/16-inch. To find the correct socket, you’ll need to check your vehicle’s manual or visually inspect the drain plug itself, as a proper fit is crucial to avoid rounding the bolt head. 
How to find the right socket size:

1. Check your vehicle’s manual: or a reliable parts website for your specific car. 
2. Visually inspect the drain plug: before you start your oil change. The size of the wrench needed corresponds to the width across the bolt’s flats. 
3. Have a basic metric socket set: on hand, as common sizes range from 10mm to 21mm, with 15mm being a frequent choice. 

Tips for success:

• Use the correct size: A socket that is too small can damage the bolt head, while one that is too large can also cause issues and damage. 
• Use a 6-point socket: This type provides a more secure fit on the bolt head, reducing the risk of stripping. 
• Clean the bolt and pan: Ensure the bolt and surrounding area are clean before reinstalling to maintain a proper seal and prevent future leaks. 
• Consider writing it down: For future reference, note the drain plug size under the hood of your car. 

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 is a standard oil drain plug?

There is no single “standard size” for an oil drain plug, as sizes vary by vehicle make and model. To find the correct size, you need to check your vehicle’s owner’s manual or measure your existing plug’s thread diameter (e.g., M12, M14) and the required wrench size for the head (e.g., 15mm, 17mm).
 
How to Determine Your Drain Plug Size

1. Check Your Owner’s Manual: This is the best first step to find the correct size specified for your vehicle. 
2. Measure Your Existing Plug:
   • Thread Diameter: Measure the widest part of the plug’s threads to get the metric (M) or standard (SAE) diameter (e.g., M12 means a 12mm thread diameter). 
   • Head Size: The head size (e.g., 17mm) is the measurement needed for the wrench or socket you’ll use to remove and install the plug. 
3. Use a Vehicle-Specific Parts Catalog: Websites for auto parts stores or manufacturers like Dorman Products and NAPA Auto Parts have tools to help you find the right drain plug by entering your vehicle’s year, make, and model. 

Common Size Examples
While not standard, here are some examples of common sizes: 

• Metric: M12 x 1.5, M12 x 1.75, M14 x 1.50.
• SAE (Imperial): 1/2-20.

What size bolt is the oil drain plug?

There is no universal bolt size for an oil drain plug; sizes vary by vehicle make, model, and year. You must determine the correct size for your specific car by checking its owner’s manual or looking up the part for your vehicle. Common sizes exist, such as M12, M14, M16, and M20, with corresponding thread pitches like 1.25, 1.5, or 1.75. 
How to Find the Correct Oil Drain Plug Size

1. Check the Owner’s Manual: This is the most reliable source for your vehicle’s specifications, including the correct thread size and type for the drain plug. 
2. Look Up Parts Online: Use a parts lookup tool for your vehicle’s make, model, and year to find the exact drain plug size you need. 
3. Inspect the Existing Plug: If the old drain plug is still in the vehicle, check for markings or measure it. However, be cautious as the wrong plug may fit but cause leaks or damage. 

Common Drain Plug Size Formats
Drain plug sizes are typically expressed in two parts: 

• Bolt Size: The diameter of the bolt, e.g., M12, M14, M16.
• Thread Pitch: The distance between the threads, e.g., x1.25, x1.5, x1.75.

For example, an M14x1.5 drain plug has a diameter of 14mm and a thread pitch of 1.5mm. 
Important Considerations

• Avoid Guessing: Using the wrong size can lead to oil leaks or a stripped oil pan, which is an expensive repair. 
• Check for a Gasket: The drain plug will require a gasket (often copper or aluminum) for a proper seal. 
• Soft Aluminum Plugs: Some recommend using a softer aluminum drain plug, as it’s more likely to damage its own threads before damaging the softer threads of the aluminum oil pan.