What size is the drain plug on an oil pan?

There isn’t a single, universal size for oil pan drain plugs. Most modern passenger vehicles use metric threads—especially M14×1.5 or M12 variants—and common wrench/hex head sizes run from 13 mm to 19 mm. The exact size depends on your vehicle’s year, make, model, and engine, so the only reliable answer is to check the service manual, look up the part by VIN, or measure the original plug and washer.

Why there isn’t one universal size

Automakers design oil pans and plugs around engine packaging, materials (aluminum, steel, or composite), and manufacturing standards. Over the past two decades, the industry has largely converged on metric threads, but legacy SAE sizes still exist on older American engines, and some newer vehicles use one-time-use plastic plug assemblies integrated into composite oil pans. As a result, the “right” size varies widely—even within a single brand—by engine family and model year.

The most common drain plug sizes today

The following list highlights sizes frequently encountered in North American and European passenger vehicles. It is indicative rather than exhaustive, and head (wrench) sizes can vary by OEM vs. aftermarket plugs.

• M14×1.5 thread: Among the most common across many brands; typical hex head 14–19 mm; crush washer inner diameter ~14 mm.
• M12×1.25 thread: Common on many Japanese applications; typical hex head ~14 mm; crush washer ID ~12 mm.
• M12×1.75 thread: Seen on various GM and other applications; typical hex head 13–15 mm; crush washer ID ~12 mm.
• M16×1.5 thread: Used on some larger engines and trucks; typical hex head 17–24 mm; crush washer ID ~16 mm.
• M20×1.5 thread: Found on certain larger-displacement or specific engine families; typical hex head 17–24 mm; crush washer ID ~20 mm.
• SAE 1/2″-20 UNF: Common on older American engines; typical hex head 1/2″–3/4″; uses matching SAE sealing washer.
• Specialty/plastic assemblies: Some late-model vehicles (e.g., certain Ford, VW/Audi, and others with composite oil pans) use replaceable plastic drain plugs or modules that are single-use and specified by part number rather than thread size.

While these sizes cover the bulk of road vehicles, exceptions are common. Always match both thread size and pitch—and use the correct sealing washer type—to avoid leaks or thread damage.

How to identify your exact size

Use the steps below to confirm the precise drain plug and washer your engine requires before you service the oil.

1. Check the owner’s manual or factory service manual for the drain plug and washer spec (thread size/pitch and torque).
2. Look up the OEM part by VIN on the automaker’s parts site or a reputable online catalog to avoid engine-to-engine confusion within the same model line.
3. Measure your existing plug: use calipers for the major diameter (e.g., ~14.0 mm for M14) and a thread pitch gauge to confirm pitch (e.g., 1.5 mm).
4. Confirm the sealing method: crush washer (aluminum/copper), bonded washer, O-ring, or integrated plastic seal—this affects fit and torque.
5. Bring the original plug to a parts counter if in doubt; many stores can size threads and match washers on the spot.
6. Verify torque spec for your engine; over-tightening is the most common cause of stripped pans, especially aluminum or composite designs.

Taking a few minutes to verify size and sealing style prevents cross-threading, seepage, and costly pan repairs. If you can’t confirm size, don’t force a plug based on “what usually fits.”

Replacement and torque best practices

Following these practical tips will help ensure a clean, leak-free oil change and protect your oil pan.

• Always install a new crush washer or seal if your design uses one; reusing washers is a common source of slow leaks.
• Typical torque ranges (verify for your engine): M12 plugs ~20–30 ft-lb (27–40 Nm), M14 plugs ~22–35 ft-lb (30–47 Nm), M16 plugs ~26–40 ft-lb (35–54 Nm). Some plastic plugs torque much lower and are single-use.
• Use a torque wrench; “snug plus a quarter-turn” risks stripping aluminum pans.
• Clean threads and the pan sealing surface; remove old washer fragments or sealant.
• Consider an OEM plug if an aftermarket head size interferes with access or skid plates.
• If threads are damaged, use an appropriate thread repair (e.g., insert/Heli-Coil) rather than an oversized self-tapping plug when possible.
• On vehicles with plastic/composite pans and one-time-use plugs, replace the plug each oil change as specified.

Correct torque and a fresh seal do more to prevent leaks than any thread sealant. When in doubt, follow the manufacturer’s spec over general rules.

Brand examples (indicative, not definitive)

These examples are common patterns seen in service, but always verify by VIN or manual because engines within a brand can differ.

• Honda/Acura: Often M14×1.5 with a 17 mm hex; many models spec ~29 ft-lb (39 Nm) and require a 14 mm ID aluminum crush washer.
• Toyota/Lexus: Many use M12 (often ×1.25) with a ~14 mm hex; trucks and some engines may use M14×1.5.
• Nissan/Infiniti: Frequently M14×1.5; hex head commonly 14–17 mm depending on plug design.
• GM: Newer engines often metric (M12×1.75 or M14×1.5); older small-blocks may use 1/2″-20 UNF.
• Ford: M14×1.5 is common; certain late-model engines with composite pans (e.g., some F-150 EcoBoost years) use a replaceable plastic drain plug/module.
• VW/Audi: Commonly M14×1.5, sometimes with an internal hex (Allen) drain plug; composite pans may specify a single-use plug.
• BMW/Mini: Frequently M12×1.5 with an aluminum crush washer; verify torque in the TIS for your engine code.
• Subaru: Often larger-than-average threads on some engines; M16 or M20 sizes appear depending on engine family—verify for EJ vs. FB/FA engines.

Treat these as starting points only; the correct part number and torque for your exact engine should drive your final choice.

Summary

There is no one-size-fits-all oil pan drain plug. The most common modern sizes are M14×1.5 and M12 variants, with wrench heads typically 13–19 mm, but specifics vary by engine and model year. Confirm via the manual or VIN-based parts lookup, match the correct crush washer or seal, and torque to spec. That diligence prevents leaks and protects your oil pan from damage.

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.

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 do I need for an oil change?

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.