Parts for your 2007 Subaru Impreza-Sump plug washers

2007 Subaru Impreza sump plug washers — what they are and why they matter

Yes, the 2007 Subaru Impreza uses a sump plug washer. Technical sources, including the Subaru Impreza 2007 Service Manual (Engine Lubrication section) and Subaru Genuine Parts listings, specify a single-use crush washer for the engine oil drain (sump) plug. Subaru commonly lists the oil drain plug gasket as a 16 mm aluminium crush type (often supplied under part number 803916010), and calls for replacement at each oil change with the drain plug tightened to approximately 44 N·m (about 33 ft‑lb).

This little washer does a big job. Sitting between the sump plug head and the oil pan, the crush washer deforms slightly as it’s torqued up. That controlled “crush” creates a reliable seal that stops oil weeping out and also spreads the load so the pan threads aren’t stressed. On EJ-series engines in the 2007 Impreza, Subaru’s own servicing guidance is to fit a new washer every time the oil is changed, because once it’s crushed, reusing it can lead to seeping, drips on the driveway, and the temptation to overtighten the plug.

For owners and workshops across Australia and New Zealand, it’s a cheap bit of insurance. Keep a few spares on hand and swap one in at each service. Stick with quality OEM-style aluminium (or equivalent copper) crush washers sized for Subaru’s 16 mm drain plug. If the car has an aftermarket drain valve or a plug with a bonded O‑ring, follow that product’s instructions, but for a standard 2007 Impreza sump plug, a crush washer is the go.

• Replace the washer at every oil change. Don’t reuse the old one.
• Wipe the sump mating face and plug clean so the washer seats flat.
• Tighten the drain plug to 44 N·m — no need to swing off a long breaker bar.
• After the first heat cycle, have a quick look for any weeping, if it’s dry, you’re golden.
• Avoid thread sealants or tape on the plug, the crush washer does the sealing.

These pointers align with Subaru’s service information: new washer each time, correct torque, and clean sealing faces. Do that, and the 2007 Impreza’s sump stays tidy and leak-free between services.

Popular questions

Does a 2007 Subaru Impreza need a new sump plug washer at every oil change?
Yes. Subaru’s service documentation calls for replacing the drain plug washer each time the oil is changed. It’s a single-use crush washer, so reusing it can compromise the seal and lead to minor leaks.

What size sump plug washer does the 2007 Subaru Impreza use?
It takes a 16 mm crush washer commonly supplied as an aluminium gasket in Subaru parts catalogues (often referenced as 803916010). Torque the drain plug to about 44 N·m to correctly crush the washer and seal the sump.

Can a copper washer be annealed and reused on a 2007 Impreza?
While copper can technically be annealed, Subaru specifies installing a new washer at each service. For the small cost and to stay within factory guidance, it’s best practice to fit a new crush washer rather than reusing or heat-treating an old one.