Parts for your 2013 Subaru Outback-Sump plug washers

2013 Subaru Outback sump-plug-washers: fitted, useful, and worth replacing

Yes—on the 2013 Subaru Outback a sump plug washer (crush gasket) is used and expected to be replaced whenever the engine oil is changed. Subaru’s 2013MY Outback/Legacy Service Manual (Engine, Lubrication section) specifies fitting a new drain plug gasket at each oil change and tightening the plug to about 44 N·m. The Subaru genuine parts catalogue for the 2013 Outback (FB25 2.5L and EZ36 3.6R) also lists a dedicated aluminium drain plug gasket for the engine’s sump plug. These factory sources confirm the washer is relevant, fitted, and a normal service item.

For the 2013 Outback, the sump plug washer’s job is dead simple but absolutely vital: it crushes slightly as the plug is tightened, creating a reliable seal between the plug and the alloy sump. That soft aluminium ring prevents annoying weeps, protects the sump face, and helps the plug reach the correct clamping load without overdoing it. It’s a small, cheap bit that saves a lot of mess.

Being a crush gasket, it’s single-use. Once squeezed, it won’t spring back evenly, so reusing it invites weeping, rounded torque readings, or the temptation to overtighten the plug. Best practice on this Subaru is to fit a new washer at every oil change—easy insurance at service time whether the vehicle runs the FB25 or the EZ36.

Good workshop habits make the difference:

• Always clean the sump sealing face and the plug before refitting—no sealants, no thread tape.
• Fit a new, correct-size aluminium crush washer, keep a couple on hand with your oil and filter.
• Tighten the plug to around 44 N·m with a torque wrench on a cold engine.
• Run the engine, then check for any seepage after a short drive.

If the old washer has cut grooves into the sump face or the plug, replace the damaged part before the next service. Under Aussie and Kiwi conditions—frequent short trips, heat, and dusty roads—oil services can come up quicker than expected, so treating the washer as a routine consumable keeps the Outback tidy and the driveway clean. It’s a tiny part that punches well above its weight in everyday reliability.

Popular questions about 2013 Subaru Outback sump-plug-washers

What size sump plug washer does a 2013 Subaru Outback use?
The vast majority of 2013 Outbacks (FB25 2.5L and EZ36 3.6R) use a 16 mm aluminium crush washer on the engine oil drain plug. If in doubt, confirm against the VIN or measure the original plug and washer before buying spares.

Can the sump plug washer be reused?
It’s designed as a single-use crush gasket. Reusing it risks weeping and can throw off torque readings, which tempts overtightening. On this Subaru, replace it with every oil change—cheap, quick, and the right way to seal the sump.

What’s the torque spec for the sump plug on a 2013 Outback?
The factory spec is around 44 N·m (about 32 ft‑lb). Tighten on a clean, dry seat with a new washer. Using a torque wrench avoids stripped threads and keeps the sump happy.