Parts for your 2016 Subaru Outback-Sump plug washers

2016 Subaru Outback sump plug washers — what they do and when to replace them

Yes, the 2016 Subaru Outback uses a sump plug washer. Subaru’s own service information calls it a drain plug gasket and specifies replacing it at every engine oil change. The Subaru Service Manual for the 2015–2019 Outback (Periodic Maintenance, Engine Oil Replacement) instructs to “install a new drain plug gasket” during refit, and the Subaru Genuine Parts Catalogue lists “Gasket – Drain Plug (16 mm), P/N 803916010” for both the 2.5i (FB25) and 3.6R (EZ36) variants. That makes the sump plug washer not just relevant, but essential for a clean, leak-free service.

On this Outback, the sump plug washer is a crush-type aluminium ring that deforms slightly when the plug is tightened. That controlled crush seals the plug against the alloy sump, preventing weeps and drips once the oil gets hot. Reusing a flattened washer can lead to annoying spots on the driveway, or worse, a slow loss of engine oil.

As part of routine servicing, it’s smart to have a fresh washer on hand for every oil change. Subaru’s procedure is to remove the old gasket, clean the mating surfaces, fit a new OEM-spec washer, and tighten the plug to the workshop spec shown in the service manual (commonly around the low-to-mid 30 N·m range for this platform—always confirm for the exact engine). Going “by feel” or over-torquing can distort the washer and risk damage to the sump threads.

Drivers in Australia and New Zealand will typically find these washers sold as single-use alloy crush gaskets. Copper versions exist, but the Subaru catalogue’s 16 mm alloy type (803916010) is the go-to. Aftermarket reusable or bonded washers aren’t recommended unless explicitly engineered for Subaru’s sump design.

Signs a washer needs attention include a faint oil halo around the plug, fresh drips after a run, or a washer that looks gouged or stuck to the sump. Given the low cost, replacing it every service is cheap insurance. Pair it with quality oil and a new filter, and the Outback’s flat-four or flat-six will stay happy for the long haul.

• Part reference: Subaru Genuine Parts Catalogue — Gasket, Drain Plug 16 mm, P/N 803916010 (2016 Outback 2.5i and 3.6R)
• Service reference: Subaru Service Manual (2015–2019 Outback/Legacy) — Engine Oil Replacement procedure specifies using a new drain plug gasket

FAQ: Do all 2016 Outback engines use the same sump plug washer?
Yes. Both the 2.5i FB25 and 3.6R EZ36 engines use a 16 mm crush washer as listed in Subaru’s parts catalogue (P/N 803916010). It’s the standard gasket Subaru specifies for this model year.

FAQ: How often should the sump plug washer be replaced on a 2016 Outback?
Every oil change. Subaru’s service procedure calls for a new drain plug gasket each time the sump plug is removed, which helps ensure a reliable seal and prevents seepage as the engine heats and cools.

FAQ: What torque should the sump plug be tightened to?
Follow the specification in the Subaru service manual for your exact engine. It’s typically in the low-to-mid 30 N·m range for this generation. Using a torque wrench is the safest way to avoid leaks or thread damage.