The standard oil drain plug on a 2007 Honda Accord uses a 14mm hex socket.
That size covers the two main engines offered that year—the 2.4-liter inline-four and the 3.0-liter V6. It's the most common head for the drain plug on the Accord's oil pan, and a 14mm socket (or roughly 9/16 inch) fits most setups. If the head has been replaced or damaged, confirm by inspecting the plug or consulting the owner's manual before forcing a tool.
Engine variants and plug size
In 2007, Honda offered two engines in North America for the Accord: a 2.4L I-4 and a 3.0L V6. For both engines, the oil drain plug uses a standard 14mm hex head. This means a 14mm socket is the go-to tool for most DIY oil changes, with a deep 14mm socket often recommended for clearance in the oil pan recess. If a prior repair used an aftermarket plug with a different head, you may need a different size; always verify by inspecting the actual plug head.
What to do if the plug doesn’t fit
If the head appears damaged or a nonstandard plug has been installed, do not force a tool. Replace the drain plug with a correct OEM or OEM-compatible part and re-check the socket size. When in doubt, consult the official service manual or have a mechanic verify the correct size.
Verification and safety tips
Before loosening, ensure the engine is cool and the car is on a level surface. Start with a fresh 14mm socket that matches the bolt head, use a breaker bar for initial loosening, and avoid using an impact that could twist or strip the head. If the socket slips or rounds the head, stop and reassess rather than continuing to force the tool.
Summary
For a 2007 Honda Accord, the standard oil drain plug size is a 14mm hex socket (about 9/16 inch). This applies to the common 2.4L I-4 and 3.0L V6 engines of that year. If you encounter a different head, verify with the manual or a professional before proceeding.