Parts for your 2011 Subaru Tribeca-Sump plug washers

2011 Subaru Tribeca sump plug washers — what they do and when to replace

Technical sources confirm the 2011 Subaru Tribeca (EZ36 3.6‑litre H6) uses a sump plug washer. The Subaru Factory Service Manual for the Tribeca’s engine lubrication section, the Subaru Genuine Parts Catalogue, and service procedures in Subaru’s Global Service Information (STIS) all specify a single‑use aluminium crush gasket for the oil drain plug, commonly supplied as a 16 mm alloy washer (Subaru p/n 803916010, superseding earlier numbers). So yes—on this model a sump plug washer is absolutely relevant and fitted from factory.

On the Tribeca, the sump plug washer is the little hero that keeps the engine oil where it should be—inside the sump. It’s a soft aluminium crush gasket that sits between the drain plug head and the sump pan. When torqued to spec, it deforms slightly to create a reliable seal, coping with heat cycles, vibration, and the expansion and contraction that happens every time the engine warms up and cools down. Without it, the plug can weep oil, or need to be over‑tightened to seal, which risks stripping threads in the alloy sump. No one wants that drama.

Because it’s designed to deform once, the washer is considered single‑use. Every oil change, it should be replaced with a fresh one. Subaru’s service literature calls this out as standard practice, right alongside fitting a new oil filter. The correct torque for the Tribeca drain plug is about 44 N·m (33 ft‑lb) with a new washer—tight enough to seal, not so tight that it chews out threads. A torque wrench is the best way to nail it.

Good servicing on a 2011 Tribeca looks like this:

• Have a new 16 mm aluminium crush washer on hand before you pull the plug.
• Clean the sump sealing face and the plug head, dirt causes leaks.
• Fit the new washer, thread the plug in by hand, then torque to spec.
• After the first drive, have a quick squiz under the car for any signs of seepage.

If someone’s reused the old washer and there’s a slight weep, don’t just crank the plug tighter. Replace the washer and torque it correctly. Genuine Subaru washers are inexpensive, and quality aftermarket equivalents are fine as long as they match the 16 mm spec. Keeping this tiny part fresh helps protect the Tribeca’s sump threads, keeps the driveway clean, and makes future servicing a breeze.

• Popular question: What size sump plug washer does a 2011 Subaru Tribeca use?

It uses a 16 mm aluminium crush washer commonly supplied under Subaru part number 803916010. Many quality aftermarket 16 mm alloy crush gaskets will also do the job if they match OE dimensions.

• Popular question: How often should the Tribeca’s sump plug washer be replaced?

Every oil change. The washer crushes once to seal properly, so reusing it increases the risk of leaks or needing excess torque on the plug.

• Popular question: What’s the correct torque for the 2011 Tribeca sump plug?

About 44 N·m (33 ft‑lb) with a new washer. Always start the plug by hand to avoid cross‑threading, then use a torque wrench for a clean, consistent seal.