Parts for your 2019 Subaru Impreza-Sump plug washers

2019 Subaru Impreza sump plug washers – what they do and when to change them

Yes, the 2019 Subaru Impreza uses a sump plug washer. Technical sources back this up: the Subaru Factory Service Manual for the FB-series engine specifies replacing the drain plug gasket whenever the engine oil is changed, and the Subaru Electronic Parts Catalogue lists an aluminium crush-type drain plug gasket for this model (commonly referenced as 16 mm “Gasket–Drain Plug,” often supplied under Subaru part number 803916010). The same documentation gives a drain plug torque of about 42 N·m (31 ft‑lb) when a new washer is fitted.

On the 2019 Impreza, the sump plug washer is a small, single‑use aluminium crush washer that sits between the steel drain plug and the alloy sump. When the plug is torqued, the washer deforms slightly to seal any microscopic gaps, so oil can’t seep out. That soft metal layer also helps the plug reach the correct clamping load without over‑stressing the sump threads—handy insurance on an alloy pan.

Because it’s designed to crush, it’s a consumable. Reusing an old washer can lead to those annoying damp weeps under the car, or a drip that shows up on the driveway after a long run. For stress‑free servicing, it’s best practice to fit a new quality washer at every oil change—whether the job’s being done at home under the bonnet or by a workshop. Most genuine Subaru washers are symmetrical, if an aftermarket washer has a tapered side, fit the flat face to the sump.

A few quick tips for tidy, leak‑free servicing on a 2019 Subaru Impreza:

• Have a new 16 mm aluminium crush washer ready before you start.
• Clean the sump sealing face and plug head so the washer sits flat.
• Screw the plug in by hand first to avoid cross‑threading, then torque to 42 N·m with the new washer.
• Run the engine, check for leaks, and recheck after the first drive.

There’s no need to “gorilla” the plug tighter, if it won’t seal at the specified torque, the washer is likely the culprit. Sticking with a genuine Subaru washer or a reputable equivalent keeps things simple. It’s a tiny part, but it does a big job—sealing the system so fresh oil can protect the FB20 engine properly over thousands of kilometres and plenty of Aussie and Kiwi conditions.

Popular questions about 2019 Subaru Impreza sump plug washers

What size washer does the 2019 Impreza use?
The 2019 Impreza uses a 16 mm aluminium crush washer for the engine oil drain plug. In Subaru parts listings it’s the oil drain plug gasket commonly supplied under 803916010. If unsure, confirm with the VIN at a dealer or trusted parts counter.

Should the washer be replaced every oil change?
Yes. It’s a single‑use crush washer designed to deform once. Reusing it risks seepage. Replacing it at each service is inexpensive insurance for a clean, dry sump and correct plug torque.

What’s the correct torque for the drain plug with a new washer?
About 42 N·m (31 ft‑lb) on the FB‑series engine. Fit a new washer, tighten to spec, and avoid overtightening—let the washer do the sealing.