Parts for your 2004 Subaru Impreza-Sump plug washers

2004 Subaru Impreza sump plug washers — do they apply, and how to look after them

Yes, the 2004 Subaru Impreza uses a sump plug washer (oil drain plug gasket). Subaru’s Factory Service Manual for the 2004 Impreza (Engine Lubrication section) calls for replacement of the drain plug gasket whenever the engine oil is changed and specifies a drain plug torque of about 44 N·m. Subaru’s parts catalogue also lists an aluminium crush-type gasket for the engine oil drain plug on 2004 EJ-series engines, commonly shown as 11126AA000, with later supersession to 803916010. Those technical references make it clear the sump-plug-washers are relevant and fitted.

This small, single-use aluminium crush washer does a big job. When the plug is tightened, the washer deforms slightly to create a reliable, leak-free seal between the plug and the alloy sump. That crush action prevents weeping, saves the sump threads from excessive torque, and keeps the driveway free of oil spots.

As part of regular servicing on a 2004 Subaru Impreza, swapping the sump plug washer every oil change is the go. It’s inexpensive insurance against leaks and stripped threads. Genuine Subaru aluminium washers are ideal, though quality aftermarket equivalents are fine if they match the correct size and thickness. Many dealers note 11126AA000 (often superseded by 803916010) as the right call for EJ20 and EJ25 engines of that era.

A few easy tips keep things tidy:

• Always fit a new crush washer, they’re designed for one use only.
• Clean the plug and sump sealing face before refitting.
• Tighten to around 44 N·m — don’t swing off it. Over-tightening can distort the washer or damage sump threads.
• Watch for tell-tales after a change: a light oil mist around the plug, a drip on the undertray, or a whiff of hot oil after a drive. If noticed, recheck torque and washer fitment.

Owners who do their own servicing often keep a few spare washers on hand. Aluminium is the OE style, copper can also work if sized correctly, but sticking with Subaru’s spec avoids hassles. For most Aussie and Kiwi service intervals (roughly every 10,000 km or 6 months, depending on use and oil), pairing fresh oil and filter with a new sump plug washer keeps the EJ engine happy and leak-free.

Popular questions about 2004 Subaru Impreza sump plug washers

Do all 2004 Subaru Imprezas use a crush washer on the sump plug?
They do. Both EJ20 and EJ25 variants run a crush-type gasket on the engine oil drain plug. Subaru’s service info specifically instructs replacing the gasket at each oil change to maintain a proper seal.

What part number is the correct washer for a 2004 Impreza?
Subaru commonly lists the oil drain plug gasket as 11126AA000, with many catalogues showing supersession to 803916010. Either genuine part (or an exact-spec equivalent) will suit the 2004 EJ-series engine’s sump plug.

How tight should the sump plug be on a 2004 Impreza?
The factory torque spec is about 44 N·m (32–33 ft·lb). Using a torque wrench helps avoid over-tightening, ensures the crush washer seals correctly, and protects the aluminium sump threads.