What size bolt is an oil pan plug?
There is no universal bolt size for oil pan drain plugs; most modern cars use metric threads around M14x1.5, but sizes can vary by engine and manufacturer. The exact bolt size and head type should be confirmed from the vehicle’s manual or by matching the original plug.
Why there isn’t a single standard
Automakers select drain plug sizes to fit the oil pan, gasket, and sealing requirements of each engine. Variations in diameter, thread pitch, and head size mean that one model may use a different plug than another, even within the same brand.
Common thread size ranges you may encounter
Thread size on oil pan drains typically falls in a few familiar metric ranges, though exact specifications vary by vehicle. The sizes below reflect what you might see on many passenger vehicles:
- M12x1.5
- M14x1.5
- M20x1.5
Head or drive sizes (the tool needed to remove the plug) commonly fall in the 14–19 mm range, but always verify for your specific plug.
How to determine the exact drain plug size for your vehicle
To ensure you get the correct bolt size and avoid cross-threading or leaks, use these steps:
- Check the owner's manual or service manual for the drain plug specification, including thread size and pitch, and the required gasket or washer type.
- Inspect the current drain plug: read any markings on the head that indicate thread size or part number.
- Measure the drain plug with calipers or a thread gauge to determine diameter and thread pitch, if you can access it safely.
- Compare the measurement to a thread-size chart or bring the old plug to an auto parts store to match a replacement part.
- When replacing, use a new washer/gasket and torque to the manufacturer’s specification; avoid using sealants that can clog oil passages.
Following these steps helps ensure you select the correct bolt size and maintain proper sealing and torque on the oil system.
Practical maintenance and replacement tips
Handling the oil pan drain plug requires care: dirty or over-torqued plugs can strip threads or cause leaks. If the plug is difficult to remove, apply penetrating oil and loosen slowly to avoid damage. Always replace the washer/gasket if your plug uses one.
- Keep a small set of common drain plug sizes in your toolbox for quick changes.
- Keep a torque wrench handy and know the vehicle’s recommended torque value before reinstallation.
- After replacing the plug and changing the oil, ensure the area is clean and the oil level is correct.
These practical steps help you manage routine oil changes without surprises.
Summary
There is no universal bolt size for an oil pan plug. Most passenger vehicles use metric threads around M14x1.5, but sizes can range from M12x1.5 to M20x1.5 or other variations depending on the engine. Always verify with the vehicle’s manual or by matching the original plug, and follow the manufacturer’s torque specifications for a proper seal.
What size is the most common oil plug?
Most cars use oil drain plugs between 13mm and 17mm, depending on the brand.
Are all oil pan drain plugs the same size?
All drain plugs are not the same because all drain pans are not the same. OE manufacturers have different designs when it comes to their vehicle, so naturally, oil drain pans, drain plugs and gaskets are different too.
What size bolt is a oil drain 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.
What tool should you use to loosen the oil pan drain plug?
The AGS Accu-Fit® Magnetic Drain Plug Removal Tool - the ultimate solution for hassle-free oil changes. This innovative tool is a must-have for anyone who wants to avoid the risks of getting burned by hot oil while changing their oil.
