What size is the oil drain bolt?

It depends on the vehicle. Most modern passenger cars and light trucks use metric oil drain plugs, with M14×1.5 (often a 17 mm or 19 mm hex head) and M12×1.25 or M12×1.75 (often a 14 mm or 17 mm hex head) being the most common. Many Hondas use M14×1.5 with a 17 mm head; many Toyotas/Nissans use M12 threads with a 14 mm head; Subarus often use M16×1.5 with a 17 mm head; motorcycles frequently use M12×1.5 with a 17 mm head. To give a precise size, please share your year, make, model, and engine.

Why the size varies

Oil drain bolt size is determined by the engine’s oil pan design, material (steel vs. aluminum), and the manufacturer’s standards. It includes two dimensions: the thread size and pitch (for example, M14×1.5) and the tool size needed to turn it (for example, a 17 mm hex head or an internal hex/Torx). Even within the same brand, different engines or years may use different plugs, and some newer vehicles use single-use plastic or aluminum plugs that are replaced at each service.

Typical drain plug sizes by brand and segment

The following list summarizes commonly encountered oil drain plug sizes and head types by brand and category. These are typical, not universal, and torque values can vary—always confirm against the service manual.

• Honda/Acura (cars): M14×1.5 thread, 17 mm hex head; typical torque around 29 lb-ft (39 N·m).
• Toyota/Lexus: Often M12×1.25 (many cars) or M14×1.5 (trucks/newer), commonly a 14 mm hex head; typical torque ~27–30 lb-ft (37–41 N·m).
• Nissan/Infiniti: Often M12×1.25 with a 14 mm head; typical torque ~25–33 lb-ft (34–45 N·m).
• Subaru: Often M16×1.5 with a 17 mm head; typical torque ~31 lb-ft (42 N·m).
• Mazda: Frequently M14×1.5 with a 17 mm head; typical torque ~22–30 lb-ft (30–41 N·m).
• Hyundai/Kia: Often M14×1.5, 17 mm head; typical torque ~25–33 lb-ft (34–45 N·m).
• VW/Audi: Commonly M14×1.5 with a 19 mm hex or 6/8 mm internal hex; many late models use single-use aluminum/plastic plugs with specific torque/angle specs.
• BMW/MINI: Often M12×1.5 or M14×1.5 with a 17 mm head or 8 mm internal hex; many specify lower torque on aluminum pans (about 25 N·m/18 lb-ft).
• Mercedes-Benz: Frequently M14×1.5 with a 13 mm head or 8 mm internal hex; some models are serviced by top-side oil extraction.
• Ford/Lincoln: Commonly M14×1.5 or M12×1.75 with 13/15 mm heads; some newer EcoBoost engines use single-use plastic, quarter-turn plugs with no conventional torque.
• GM/Chevrolet/GMC/Cadillac: Often M14×1.5 with 13 or 15 mm heads; aluminum pans typically call for ~18–25 lb-ft (24–34 N·m).
• Motorcycles (Japanese): Frequently M12×1.5 with a 17 mm head; typical torque ~22–30 N·m (16–22 lb-ft) with a 12 mm ID crush washer.

Use these as starting points only. Variations exist by engine family and model year, and some platforms switch to single-use plugs or different head types mid-generation.

How to find your exact drain bolt size

If you don’t have the service spec handy, these steps will help you identify the exact thread, pitch, and head type for your vehicle’s drain plug.

1. Check the owner’s manual or factory service manual: Many list the drain plug size and torque (and note if the plug or washer is single-use).
2. Use the OEM parts catalog with your VIN: Dealer parts sites and manufacturer catalogs will show the exact plug part number and its dimensions.
3. Look for markings: Some plugs have the thread pitch stamped or etched; washers are sized to the thread (e.g., 12 mm, 14 mm, 16 mm ID).
4. Measure the removed plug: Use calipers to measure major diameter (e.g., ~14.0 mm for M14) and a metric thread pitch gauge to confirm pitch (1.25, 1.5, 1.75).
5. Confirm the head/tool type: External hex (common), internal hex (Allen), Torx, or plastic quarter-turn on some newer models.
6. Avoid guessing on torque: Once you know the exact plug and pan material, use the manufacturer’s torque spec.

These checks prevent thread damage and ensure you have the correct crush washer and torque, which are critical for sealing and pan longevity.

Torque and washer quick guide

Correct torque and a fresh washer are as important as the plug size. Here are common pairings and typical ranges seen across manufacturers, to be verified against your service manual.

• M12 plugs (common on many cars): 25–30 lb-ft (34–40 N·m); washer typically 12 mm ID × ~18 mm OD copper/aluminum.
• M14 plugs (very common): 25–33 lb-ft (34–45 N·m); washer typically 14 mm ID × ~22 mm OD.
• M16 plugs (e.g., many Subaru): 31–36 lb-ft (42–49 N·m); washer typically 16 mm ID × ~24 mm OD.
• Aluminum pans or single-use plugs: Often lower torque or torque-plus-angle; follow the exact factory spec to avoid stripping.
• Plastic, quarter-turn plugs (some Ford/VW/Audi): Replace each service; install per angle/turn instructions rather than a torque value.

Always replace the crush washer unless your plug uses an integrated seal. Over-tightening can strip threads or deform the washer, causing leaks.

Caveats and special cases

Not every vehicle uses a conventional metal drain bolt, and some platforms deviate from common patterns.

• Single-use plugs and seals: Increasingly common; plan to replace the plug each oil change (check the parts catalog).
• Top-side extraction systems: Some European models are serviced via the dipstick tube with no pan drain plug removal.
• SAE threads on older domestic vehicles: Rare on modern cars, but older models may use UNF threads (e.g., 1/2-20) with 1/2″ or 9/16″ heads.
• Aftermarket pans or magnetic plugs: Sizes may differ from OEM; confirm the thread and washer spec stamped on the aftermarket part.

If your vehicle falls into one of these categories, the manufacturer’s instructions take precedence over general guidance.

Quick tools checklist

Having the right tools on hand prevents damage and speeds up the job.

• Metric socket set (13, 14, 15, 17, 19 mm are the most common) and/or internal hex/Torx bits as required.
• Calipers and a metric thread pitch gauge (if measuring a removed plug).
• New crush washer (size to match plug) or new single-use plug as specified.
• Torque wrench calibrated in N·m/lb-ft for accurate tightening.
• Drain pan, gloves, shop towels, and brake cleaner for cleanup.

With these tools and the correct spec, you can change oil confidently and avoid leaks or stripped threads.

Summary

The oil drain bolt size isn’t one-size-fits-all. M14×1.5 and M12 (1.25 or 1.75 pitch) are the most common for cars, with head sizes typically 14, 17, or 19 mm, while Subarus often use M16×1.5 and many motorcycles use M12×1.5. Share your exact year, make, model, and engine to identify the precise thread, head type, torque spec, and washer you need.

What size socket do you need for oil?

Ratchet and Socket Set
Get a set that includes some metric and SAE sizes, and if you’re starting out, a 3/8” drive should do just fine. Ratchets and sockets also come in 1/4, 1/2″, 3/4″, and 1” drives. Many medium sized kits will include ratchets and sockets in 3/8” and 1/2″ drive.

Are all oil drain bolts the same?

Different oil drain plugs and Gaskets are required for different vehicles. Drain plugs & gaskets vary from make, model, and even year. We recommend always checking your owners manual or any parts lookup like our Application Search to find the right drain plug.

What size socket is the oil drain plug?

The oil drain plug size varies by vehicle, but 14mm, 15mm, 17mm, and 19mm are common metric sizes, while some older vehicles or specific makes might use 3/4-inch or 7/8-inch imperial sockets. To find the exact size for your car, you’ll need to check your vehicle’s owner’s manual or consult the RockAuto website, as there is no universal size. 
How to find the correct socket size:

1. Check your owner’s manual: Your vehicle’s owner’s manual will provide the exact specification for your oil drain plug. 
2. Consult online resources: Websites like RockAuto.com are excellent resources for finding specific part information for your vehicle’s make and model. 
3. Physical inspection: If you have some tools available, you can try fitting common metric sizes like 14mm, 15mm, 17mm, or 19mm to see which one fits correctly and doesn’t strip the bolt head. 

Important Considerations: 

• Use a 6-point socket: When using a socket on an oil drain plug, a 6-point socket provides a better grip and is less likely to strip the bolt head than a 12-point socket, especially if the plug is overtightened.
• Replace the plug if damaged: If the plug’s hex head is already rounded or stripped, you may need to replace it and use a tool like Vise-Grips to remove it.

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.