How to Find Your Oil Drain Plug Size

The fastest way to find your oil drain plug size is to check your vehicle’s owner’s manual or an OEM parts catalog using your VIN; if that’s unavailable, remove the plug and measure its thread diameter and pitch with a caliper and thread gauge. Common automotive sizes include M14×1.5, M12×1.25, M12×1.75, and M16×1.5, but you should verify your exact spec, use the correct crush washer, and torque to the factory value to prevent leaks or stripped threads.

Why the Oil Drain Plug Size Matters

Using the correct drain plug and washer ensures a reliable seal, proper torque, and thread integrity in the oil pan. The wrong size can cause slow leaks, cross‑threading, or catastrophic pan damage. Because thread size and pitch vary by make, model, engine, and sometimes production year, confirming your exact specification saves time and avoids costly repairs.

Quick Ways to Look Up Your Exact Size

Before taking anything apart, try these reliable lookup methods that typically yield the precise thread size, pitch, and washer specification for your specific vehicle.

• Owner’s manual or factory service manual: Many list the drain plug and washer specs and torque values.
• OEM online parts catalogs: Enter your VIN on the automaker’s site (e.g., Toyota, Honda, Ford, GM, BMW, Mercedes-Benz) to view the drain plug part number and washer size.
• Dealer parts department: Provide your VIN; ask for the oil drain plug thread size/pitch and washer type.
• Trusted aftermarket catalogs: Quality suppliers (e.g., Dorman, Fumoto, Mahle) list thread size/pitch by application—cross‑check against OEM data.
• Community/club forums and TSBs: Useful for platform-specific quirks, but always verify with OEM data.

Confirming via VIN-based sources minimizes the chance of mismatch, especially on vehicles with mid‑cycle part changes or multiple engine options.

How to Measure Your Drain Plug (Step-by-Step)

If documentation isn’t available, you can identify the size by measuring the plug you have. The following steps outline an accurate approach using common hand tools.

1. Clean the plug: Wipe off oil and debris so threads are clearly visible.
2. Measure thread diameter: Use a caliper across the outer thread peaks (major diameter). Metric results like 12.0 mm, 14.0 mm, or 16.0 mm are typical.
3. Determine thread pitch: Use a metric thread pitch gauge; common pitches are 1.25, 1.5, or 1.75 mm. Without a gauge, count thread peaks over 10 mm and divide by the count.
4. Check if threads are straight or tapered: Engine oil drain plugs are almost always straight metric threads that seal with a washer; tapered pipe threads (NPT) are rare on engine pans.
5. Note the under‑head features: Identify the washer type (crush washer, bonded washer), magnet tip, and the head style (hex size) for tool selection.
6. Inspect the pan port: Ensure threads in the pan are clean and not galled or previously repaired with inserts.

Combining major diameter and pitch gives you the format (e.g., M14×1.5). Record the washer size and type at the same time so you can replace it correctly.

Common Oil Drain Plug Thread Sizes

While you must verify your vehicle’s exact spec, these thread sizes are frequently encountered on passenger vehicles and light trucks.

• M14×1.5: Very common across many Japanese, European, and North American applications.
• M12×1.25: Common on various Japanese engines; verify washer size carefully.
• M12×1.75: Used by some manufacturers; don’t confuse with 1.25 pitch.
• M16×1.5: Seen on larger engines and some trucks/SUVs.
• 1/2″-20 UNF or 1/2″-13 UNC: Found on some older domestic vehicles; less common on modern engines.

Treat these as typical—not universal—sizes. Always confirm by VIN lookup or measurement because exceptions are common, even within the same model line.

Don’t Confuse Socket Size with Thread Size

The hex head you put a wrench on is not the same as the thread diameter. A plug that takes a 17 mm socket, for example, might have M14 threads. Identify the thread by measuring the threaded portion or looking up the spec—never by the wrench size on the head.

Washers and Sealing: What to Use

The washer is critical for sealing. The following points help you select and install the correct washer for your plug and pan material.

• Match washer I.D. to thread size: M14 plug usually uses an M14 washer, etc.
• Material matters: Aluminum crush washers are common; copper and steel-bonded rubber washers are also used. Follow OEM recommendations.
• Single-use vs. reusable: Aluminum and copper crush washers are typically single-use; replace at every oil change.
• Pan material: Aluminum pans are more sensitive to over‑torque—use a fresh crush washer and torque correctly.
• Surface condition: Ensure mating surfaces are clean and flat to avoid seepage.

Using the correct, fresh washer often solves minor drips without resorting to sealants or excessive torque, both of which can cause damage.

Torque Guidance (Always Verify OEM Spec)

Over‑tightening is a common cause of stripped pans. Use a torque wrench and follow factory specs. Typical values for passenger vehicles fall within these ranges:

• M12 plugs: roughly 20–30 N·m (15–22 lb‑ft)
• M14 plugs: roughly 25–40 N·m (18–30 lb‑ft)
• M16 plugs: roughly 30–45 N·m (22–33 lb‑ft)

These are general ranges only; consult your service manual or OEM catalog for the exact torque for your engine and washer type.

If Threads Are Damaged or Size Is Unclear

Sometimes you’ll discover damaged threads or a non‑standard repair. Here’s how to proceed safely.

• Inspect for cross‑threading: If threads are crushed or angled, stop and repair before reinstalling.
• Use a thread chaser, not a cutting tap: A chaser cleans and reforms minor damage without removing excess material.
• Helicoil/insert repair: For stripped aluminum pans, a properly installed insert restores the original size and often outlasts the pan.
• Avoid oversize “self‑tapping” plugs unless it’s an emergency: They can complicate future repairs.
• Consider an OEM‑spec drain valve (e.g., with M14×1.5 threads) only after you confirm exact thread size and sealing method.

When in doubt, consult a professional; improper repairs can escalate into pan replacement, which is far more expensive.

Signs You Have the Wrong Plug or Washer

After installation, pay attention to these indicators that something doesn’t match your vehicle’s specification.

• Plug seats before reaching torque or keeps spinning: Threads may be wrong or damaged.
• Persistent drip even with new washer: Washer type/size may be incorrect, or mating surfaces are marred.
• Excessive resistance on first turns: Possible cross‑threading—stop and inspect.
• Magnet or tip length interference: Incorrect plug length can contact internals in shallow pans.

Catching these signs early prevents leaks, contamination, and costly thread repairs.

Where to Buy the Correct Plug and Washer

Once you know your spec, sourcing is straightforward. OEM parts ensure exact fit, while reputable aftermarket options can add features like magnets or valves.

• Dealer parts counters and official OEM parts websites by VIN for exact part numbers.
• Reputable parts retailers with VIN lookup and spec listings.
• Aftermarket brands that publish thread size and washer compatibility clearly.

Cross‑check the thread size, pitch, and washer type across sources to avoid look‑alike but incompatible parts.

Pro Tips

These quick tips help ensure a clean, damage‑free oil change related to the drain plug.

• Warm oil drains faster, but let metal cool slightly to avoid burns and soft aluminum threads.
• Start the plug by hand for several turns before using a wrench—this prevents cross‑threading.
• Replace crush washers every oil change; they’re inexpensive insurance against leaks.
• Wipe the area dry after tightening; recheck for seepage after the first drive.
• Record the size and torque in your maintenance log for next time.

A consistent routine with proper parts and torque keeps the pan threads healthy for the life of the vehicle.

Summary

To find your oil drain plug size, look it up by VIN in an OEM catalog or your service manual; if that’s not available, remove and measure the plug’s major diameter and thread pitch. Confirm the correct crush washer, and torque to the factory spec—don’t rely on the socket size of the plug head. Common sizes like M14×1.5 and M12×1.25 appear often, but verification is essential to avoid leaks and thread damage.

Are all oil 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.

How do I know what size drain plug I need?

The Key to a Perfect Fit

1. Measure the Diameter: Use a measuring tape or ruler to determine the diameter of the drain mesh or the underside of your existing sink plug.
2. Consider the Type: Keep in mind the type of sink you have.
3. Check the Options: Manufacturers offer various sizes beyond the standard.

How to find out oil drain plug size?

Measure Diameter
Measure the width of the plug at the widest part of the threads. If your plug measures 12mm you will need to start looking at plugs in the size range of “M12 x 1.25 to M12 x 1.75″. The “M12” refers to the diameter you measure from the widest part of the threads on your OEM sump plug.

How to identify an oil drain plug?

It’s usually easy to spot a vehicle’s oil drain plug, because it’s positioned at the lowest possible point on the oil pan, which is itself attached to the very bottom of your vehicle’s engine. The plug isn’t always located on the bottom side of the pan.