What size is the oil drain plug on a 2018 WRX?
The oil drain plug on a 2018 Subaru WRX uses a 14mm hex head and a standard M20 x 1.5 thread, paired with a crush washer.
Plug size and identification
The 2018 WRX, which uses the FA20D turbo engine, employs a drain plug that is operated with a 14mm hex socket. The threaded portion is M20 x 1.5, and a crush washer is used on the plug. If you’re replacing the plug, choose an OEM-style crush washer designed for an M20 x 1.5 drain plug.
Locating and verifying the plug
The drain plug sits on the underside of the engine oil pan and can be accessed from beneath the vehicle with the car safely raised. If you’re unsure, consult the owner's manual or a service manual for the exact location and specifications for your vehicle.
Tools and materials checklist
- 14mm socket or wrench for the drain plug head
- Crush washer compatible with M20 x 1.5 plug (OEM style)
- Oil drain pan to catch the old oil
- Appropriate engine oil for your WRX (check owner’s manual for grade and capacity)
- Rags or shop towels for cleanup
Note: After reinstalling the drain plug and refilling with oil, inspect for leaks and ensure the washer seats properly.
Additional context and tips
While the plug size is standard, always verify against your vehicle’s service manual or a trusted parts diagram, as minor variations can occur by market or engine revision. If you’re switching to an aftermarket drain plug, confirm the thread size and compatibility with the FA20 engine’s oil pan to avoid cross-threading or leaks.
Summary
For a 2018 WRX, the oil drain plug features a 14mm hex head with M20 x 1.5 thread and uses a crush washer. Use the correct washer, follow the service manual for torque and installation guidelines, and replace the washer at every oil change to prevent leaks.
