What Size Is the Oil Drain Bolt for an Oil Change?

There isn’t one universal size: most passenger vehicles use a metric oil drain plug with a 13–19 mm hex head—most commonly 14 mm or 17 mm—and threads such as M12×1.25/1.5, M14×1.5, or M16×1.5; typical tightening torque falls around 18–33 ft‑lb (25–45 N·m), but you should always follow the vehicle’s service manual. The “right size” depends on both the head/socket size and the plug’s thread diameter and pitch, plus the correct crush washer for sealing.

What “size” actually means for an oil drain bolt

When people ask for the bolt size, they may mean the socket size that fits the bolt head, or the plug’s thread diameter and pitch, which determines compatibility with the oil pan and the crush washer. Both matter: the hex size tells you which socket to use; the thread size ensures you don’t cross‑thread or leak oil; and the washer size must match the thread to seal properly.

Common drain plug head/socket sizes

Across modern passenger cars and light trucks, these are the hex head sizes you’re most likely to encounter. Keep in mind that exceptions exist, and some European models use internal hex (Allen) or Torx-style plugs.

• 13 mm
• 14 mm (very common)
• 15 mm
• 17 mm (very common)
• 19 mm
• SAE holdovers on older U.S. vehicles: 1/2″, 9/16″, 5/8″, 3/4″

In practice, a 14 mm or 17 mm socket covers a large share of cars, while some trucks and European models lean toward 15 mm or 19 mm, or use internal hex plugs.

Typical thread diameters and pitches

The thread specification determines the plug’s fit in the pan and the crush washer size. These are the most common thread combinations on mass-market vehicles.

• M12 × 1.25
• M12 × 1.5
• M14 × 1.5
• M16 × 1.5
• Less common but seen on some European/performance models: M18 × 1.5

The correct crush washer (aluminum, copper, or fiber) will match the plug’s thread size—e.g., 12 mm, 14 mm, or 16 mm inner diameter—and is essential to prevent seepage.

Examples by brand (typical, not universal)

The following combinations are common patterns, offered for guidance only. Always confirm with your owner’s/service manual or OEM parts lookup by VIN, as model-years and engines vary.

• Honda/Acura: 17 mm hex, M14 × 1.5 thread; torque about 29 ft‑lb (39 N·m); 14 mm ID aluminum crush washer.
• Toyota/Lexus: Often 14 mm hex, M12 × 1.25 or M14 × 1.5 depending on engine; torque typically 27–30 ft‑lb (37–41 N·m); 12 or 14 mm ID washer.
• Subaru: 17 mm hex, frequently M16 × 1.5; torque about 31–33 ft‑lb (42–45 N·m); 16 mm ID washer.
• Nissan/Infiniti: Commonly 14 mm hex with M12 × 1.25 or M14 × 1.5; torque 25–33 ft‑lb (34–45 N·m); matching 12/14 mm washer.
• Ford: Many steel plugs use 15 mm hex with M14 × 1.5; some late‑2010s+ engines and trucks use plastic, one‑time‑use drain plugs with O‑rings—follow the exact replacement and torque in the manual.
• GM/Chevrolet/GMC: Often 13 or 15 mm hex; M14 × 1.5 is common on trucks; typical torque 18–25 ft‑lb (25–34 N·m), but verify by engine.
• VW/Audi: External 19 mm hex or internal hex (e.g., 6/8 mm), commonly M14 × 1.5 or M18 × 1.5; many aluminum pans specify a new washer or plug each change; torque often 22–30 ft‑lb (30–40 N·m).
• BMW/MINI: Frequently internal hex or 17 mm external; M12 × 1.5 or M14 × 1.5; many aluminum pans require a new sealing washer or plug; torque typically 18–25 ft‑lb (25–34 N·m).
• Hyundai/Kia: Often 17 mm hex, M14 × 1.5; torque commonly 25–33 ft‑lb (34–45 N·m); 14 mm ID washer.

Treat these as starting points. Even within a brand, specific engines, pans, and mid‑cycle updates can change the plug and washer spec.

How to find your exact size

Because plug designs vary—even on the same model across years—the fastest way to avoid mistakes is to confirm the exact part and torque for your VIN or engine code. Here’s a practical workflow.

1. Check the owner’s or service manual for drain plug size, washer part number, and torque spec.
2. Use an OEM parts catalog or dealer lookup by VIN to get the exact plug and washer part numbers and thread size.
3. Measure the old plug: hex across‑flats (socket size), thread diameter (caliper), and pitch (thread gauge). Avoid guessing by eye.
4. Test‑fit sockets before loosening; if it feels sloppy, stop and choose a snugger size to prevent rounding.
5. If the plug looks non‑metallic (plastic/composite) or has an O‑ring, it may be single‑use—buy the correct replacement ahead of time.
6. When in doubt, a reputable parts counter can match the plug/washer if you bring the VIN or the old parts.

Confirming these details upfront saves time, prevents damage to the oil pan threads, and ensures a leak‑free seal after the oil change.

Torque and sealing best practices

Most M12–M14 plugs in aluminum pans land around 18–30 ft‑lb (25–40 N·m), and M16 plugs or steel pans can be a bit higher—but over‑torqueing is the most common cause of stripped pans and leaks. Always use a new crush washer unless the design uses a reusable O‑ring specified by the manufacturer.

Follow these quick best practices to get it right.

• Replace the crush washer every oil change (aluminum or copper; match the thread size: 12, 14, or 16 mm ID).
• Start the plug by hand to avoid cross‑threading; it should spin several turns freely before tightening.
• Clean the mating surfaces and plug threads; remove old washer remnants or debris from the pan.
• Use a torque wrench set to the manual’s spec; don’t “go by feel,” especially with aluminum pans.
• If your vehicle uses a one‑time‑use plastic plug or integrated seal, install a new one and torque exactly as specified.
• After filling oil, run the engine briefly and check for drips; re‑verify torque if needed.

Consistent torque and a fresh, correct washer or O‑ring are the difference between a clean job and a slow, messy leak.

Tools and spares to keep on hand

Having the right mix of sockets and consumables makes oil service faster and safer, especially when working across multiple vehicles or unknown sizes.

• Socket set with 13–19 mm and common SAE sizes; 6‑point sockets reduce rounding.
• Internal hex (Allen) bits—6 and 8 mm are commonly used on Euro drain plugs.
• Torque wrench covering roughly 10–50 ft‑lb (14–68 N·m).
• Caliper and thread pitch gauge for verifying plug specs.
• Assorted crush washers (12, 14, 16 mm ID) or the OEM washer for your vehicle.
• Replacement drain plug matched to your VIN or thread size, in case the old one is rounded or damaged.
• Drain pan, gloves, rags, and brake cleaner for cleanup.

A small investment in the correct sockets, torque wrench, and washers eliminates the most common oil‑change headaches.

Red flags and exceptions

Some vehicles diverge from the simple steel bolt and crush washer approach. Watch for these scenarios and consult the manual before proceeding.

• Plastic or composite, quarter‑turn drain plugs with O‑rings (common on some late‑2010s+ Ford and European models)—often single‑use with specific torque.
• Aluminum oil pans specifying a new plug each time or special sealing washers.
• Oversize “repair” drain plugs indicating prior thread damage; consider installing a proper insert (e.g., Heli‑Coil/Time‑Sert) to restore OEM size.
• Skid plates or undertrays that hide multiple plugs—ensure you’re loosening the engine oil drain, not the transmission or differential.

If anything looks unusual, stop and verify the exact part and procedure to avoid costly pan or thread repairs.

Summary

There is no single oil drain bolt size. Most cars use a 14 mm or 17 mm socket on a metric plug with threads like M12×1.25/1.5, M14×1.5, or M16×1.5, tightened around 18–33 ft‑lb—but always follow your vehicle’s specific spec and use the correct new crush washer or O‑ring. Confirm by manual or VIN lookup, measure if needed, and torque precisely for a clean, leak‑free oil change.

What size tool do I need to change 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.

What size socket is an oil pan bolt?

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 size is the oil change bolt?

There isn’t a single “oil change bolt size” because sizes vary by vehicle. To find the correct size for your car, you must identify the specific drain plug bolt head size for your vehicle’s make and model. You can typically use a socket wrench set with common metric sizes like 14mm, 15mm, 17mm, or 19mm. If you don’t know the size, you can buy a vehicle-specific part or use a tool to measure the bolt, such as digital calipers, but a wrench that is too small can strip the head. 
How to Find the Right Size

1. Check Your Vehicle’s Owner’s Manual: Opens in new tabYour manual will often have the specific size of the drain plug. 
2. Consult an Auto Parts Store: Opens in new tabTell the store your vehicle’s year, make, and model, and they can look up the correct size. 
3. Measure the Bolt: Opens in new tabIf you have calipers or a ruler, you can measure the width of the bolt head to determine its diameter. 
4. Test Common Socket Sizes: Opens in new tabIf you don’t know the size, you may have to try the common metric socket sizes in the 14mm to 19mm range. 

Important Tips

• Use the Correct Tool: Use a socket or wrench that fits the bolt head snugly to avoid stripping it. 
• Replace the Washer: Always use a new crush washer when reinstalling the drain plug to prevent leaks. 
• Use a Proper Socket: For best results, use a 6-point socket, as these provide a more secure grip than 12-point sockets and reduce the risk of stripping. 

What size socket is needed 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.