What size Engine Oil Drain Plug?

There is no universal size for engine oil drain plugs—the thread diameter and head size vary by engine and oil pan design.

This article explains how sizes differ, how to determine the correct plug for your vehicle, and best practices for replacement and maintenance.

Why the size varies

Drain plugs are customized to fit each engine’s oil pan, factoring in the pan thickness, thread pitch, and gasket or crush washer requirements. As a result, you’ll see a range of thread sizes and socket heads across different makes and models.

How to determine the correct size for your vehicle

To identify the right plug size, use a combination of official documentation, measurements, and trusted cross-references.

1. Check the vehicle’s owner’s manual or service manual for the drain plug specifications (thread size, pitch, and torque).


2. Look up the OEM parts diagram or the dealer’s online catalog for the exact drain plug size for your year/make/model.


3. If you can access the old plug, measure its hex head size with a socket and estimate the thread size by measuring the outside diameter and pitch, or use a thread gauge.


4. Cross-reference with a reputable parts retailer or the vehicle’s VIN to confirm the correct plug and washer configuration.


5. Install a new crush washer or gasket and torque the plug to the manufacturer’s specification when reinstalling.

By following these steps, you’ll identify the correct plug size and reduce the risk of cross-threading or leaks.

Common thread-size families you may encounter

Here’s a quick reference to the main categories you’ll see across different engines.

• Metric threads: M12x1.25, M14x1.5, M20x1.5 are common on many passenger cars and light trucks.


• Imperial threads: 1/2"-20 and similar sizes appear on some older American engines or specialty applications.

Note: This is not an exhaustive list. Always verify the exact size for your specific engine through official documentation or a trusted parts source.

Practical replacement and maintenance tips

Once you know the correct drain plug size, these maintenance practices help ensure a proper seal and long life for your oil system.

• Always replace the crush washer or gasket whenever you remove and reinstall the drain plug.


• Torque the drain plug to the manufacturer’s specification to avoid leaks or stripped threads.


• Inspect the drain plug and oil pan threads for damage; replace the plug if threads are damaged.


• Consider using a magnetic drain plug if the vehicle’s manual approves it, to collect ferrous debris.

Adhering to these steps reduces the risk of leaks and other issues during oil changes.

Summary

In short, there is no single universal drain plug size. Identify the correct size for your vehicle via the owner’s or service manual, OEM diagrams, or precise measurement, and always follow the recommended torque and gasket guidelines to maintain a proper seal.

What size oil drain plug do I need?

There is no universal size for an oil drain plug, so you must determine the correct size for your specific vehicle by checking the owner's manual or using the original plug to measure it. To find the right replacement, you can look up the part by your vehicle's make, model, and year online, or by taking the old plug to an auto parts store to have it measured and identified.
 
Ways to find the correct oil drain plug size

• Check your owner's manual: This is the most direct method for finding the OEM specifications for your vehicle. 
• Look up by vehicle information: Use the make, model, and year of your vehicle to search online parts databases from auto parts stores or parts suppliers. 
• Measure the original plug: 
  • Diameter: Use calipers to measure the widest part of the threads in millimeters for metric sizes, or in inches for SAE sizes. 
  • Thread pitch: Use a thread pitch gauge to determine the distance between the threads (in millimeters) or the number of threads per inch (for SAE). 
• Consult an auto parts store: Bring the old plug to a local auto parts store, where an employee can help you find the correct size and type of replacement. 

Important considerations

• Metric vs. SAE: Many modern vehicles use metric sizes like M12x1.75, while older or American-made vehicles might use SAE sizes like 1/2 inch. 
• Head size: The size of the wrench needed to remove the plug (e.g., 15mm or 17mm) is different from the thread size and is determined by the original plug's head. 
• Replace the gasket: Always replace the drain plug gasket when installing a new plug to prevent leaks. 
• Stripped threads: If the threads on your oil pan are stripped, you will need an oversized or universal replacement plug. 

What size socket do I need to take the oil?

The correct socket size for an oil plug depends on your car's make and model, as there is no single universal size. Common metric sizes include 14mm, 15mm, 17mm, and 19mm, while some older vehicles may use SAE sizes like 3/8" or 1/2". Always inspect the plug to confirm the size, as using the wrong socket can damage the bolt head. 
You can watch this video to learn how to change the oil in a Honda CR-V, including removing the drain plug: 1m1A Auto: Repair Tips & Secrets Only Mechanics KnowYouTube · Aug 13, 2018
How to find the right size

• Check your owner's manual: This is the most reliable way to find the correct size for your specific vehicle. 
• Inspect the plug: Visually examine the drain plug to determine its size. You can also measure it with a caliper if needed. 
• Try common sizes: If you can't find your manual, start with common metric sizes like 14mm, 15mm, 17mm, or 19mm. 
• Use the right socket type: A 6-point socket is recommended over a 12-point socket to prevent stripping the bolt head. 

This video demonstrates how to use a drain plug removal tool with a magnetic feature: 52sScavenger1320YouTube · Feb 23, 2024
Important tips

• Use the correct socket: A well-fitting socket is crucial to avoid rounding the bolt head. 
• Tighten properly: Do not overtighten the drain plug, as this can strip the threads. Tighten it to the manufacturer's specifications, or just snug it up if you don't have a torque wrench. 
• Replace the crush washer: It is a good practice to replace the crush washer on the drain plug to ensure a proper seal. 

What size socket do I need to remove a drain plug?

There is no universal drain plug socket size, as it varies by vehicle make and model. Common sizes include metric sizes like 14mm, 15mm, and 17mm, as well as SAE sizes like 3/8" and 9/16". To find the correct size, check your vehicle's owner's manual, but it is recommended to have a set with both SAE and metric sockets to cover the most common sizes.
 
This video demonstrates how to find the correct size for your oil drain plug: 55s1A Auto: Repair Tips & Secrets Only Mechanics KnowYouTube · Feb 16, 2024
Common sizes

• Metric: 10mm, 14mm, 15mm, 17mm, 19mm, 21mm 
• SAE: 3/8 inch, 9/16 inch 
• Square drive: Some plugs, especially on gearboxes, may require a square drive, such as an 8mm square socket 

What to do

• Check the owner's manual: This is the most reliable way to determine the correct size for your specific vehicle. 
• Get a socket set: Purchase a socket set that includes a range of both metric and SAE sizes. This will cover the most common sizes you might encounter. 
• Use the right tool: A 6-point socket is often recommended for drain plugs to provide better grip and prevent stripping the plug, especially if it's overtightened. 

What wrench do you need to change oil?

You will need an oil filter wrench and a wrench for the oil drain plug, which is typically a socket with a ratchet or a combination wrench in a specific size. The correct size for the drain plug varies by vehicle, but common sizes are $13$mm or $15$mm. You will also need an oil filter wrench that fits your specific oil filter, as there are various types, such as strap, cap, or claw-style wrenches.
 
This video provides a quick list of all tools needed for an oil change: 56sFix Car YourselfYouTube · Aug 31, 2023
Tools for oil drain plug

• Socket wrench and socket set: A ratchet is used with a socket to fit the drain plug. Common drive sizes are 3/83 / 83/8 inch or 1/21 / 21/2 inch. 
• Combination wrench: If you don't have a socket set, a combination wrench with both an open and a closed end can work. 
• Adjustable wrench: While less ideal, an adjustable wrench can be used in a pinch, but it's easier to strip the bolt head. 

Tools for oil filter

• Oil filter wrench: These are specifically designed to grip the filter and are essential for removing one that is too tight to turn by hand. 
• Strap wrench: A strap that wraps around the filter, offering a gentle grip. 
• Cap wrench: A cap that fits over the end of the filter and attaches to a socket or ratchet. 
• Claw wrench: Jaws that grip the outside of the filter. 

Other important tools

• Torque wrench: To tighten the drain plug to the manufacturer's specifications, preventing leaks or damage. 
• Funnel: To pour the new oil into the engine. 

Before you begin

• Consult your car's manual to find the correct size for the drain plug and oil filter. 
• Warm up the engine slightly to thin the oil before draining it. 
• Place a drain pan under the plug to catch the old oil.