What size is the oil drain plug washer on a Honda?
There isn’t a single universal size for all Honda engines—the oil drain plug washer you need depends on your engine’s drain plug thread. In practice, many Hondas use an M14 x 1.5 drain plug with a copper crush washer, while some smaller engines use M12 x 1.25.
Common sizes used on Honda engines
In practice, the two most frequent configurations are M14 x 1.5 and M12 x 1.25. The exact size is determined by the engine family and model year. Always verify with the OEM parts catalog or your service manual, since the washer size is tied to the drain plug thread.
Below are the two sizes you are most likely to encounter on standard Hondas, along with notes on how to identify them:
- M14 x 1.5 drain plug — common on many Honda 4-cylinder engines (Civic, Accord, CR-V in several generations). The copper crush washer for this size is sized to fit an M14 thread and the pan seating surface.
- M12 x 1.25 drain plug — less common, found on some smaller or older Honda engines. The corresponding copper washer is smaller to match the M12 thread.
In short, the most common configuration you’ll encounter is M14 x 1.5 with a copper crush washer; older or smaller engines may use M12, and the exact size should be confirmed for your specific model.
Practical notes on fit and replacement
Use a fresh copper crush washer sized for your drain plug thread; never reuse a crushed washer. Apply a light coat of clean engine oil to the new washer and torque the drain plug to the manufacturer’s specification. If you’re unsure of the size, consult your vehicle’s service manual or Honda OEM parts catalog to avoid leaks or damage.
How to determine the correct size for your Honda
If you’re unsure of the size, here’s how to determine the correct washer for your car:
- Identify your engine code and model year from the VIN, owner’s manual, or service documentation to find the correct drain plug specification (M14 x 1.5 or M12 x 1.25).
- Check the service manual or Honda OEM parts catalog for the drain plug gasket size or part number by model/year/engine code.
- Inspect the current drain plug or old washer: the inner bore should match the bolt diameter, and the outer diameter should seal properly on the oil pan.
- Order the correct washer from Honda or an aftermarket supplier using your model/year and engine code; bring the old washer if possible to verify size.
With the right washer, reinstall the drain plug and torque to spec. Do not overtighten, as that can damage the oil pan or threads.
Summary
Honda oil drain plug washers are not universal; the most common setup uses a copper crush washer for an M14 x 1.5 drain plug, while some engines use M12 x 1.25. Always verify the exact size for your specific model via the service manual or OEM parts catalog, and replace the washer whenever you remove the drain plug to ensure a proper seal.
