Parts for your 2005 Toyota Bb-Sump plug washers

2005 Toyota bB sump plug washers

Based on Toyota’s Electronic Parts Catalogue for the NCP30/NCP31 bB (1NZ‑FE/2NZ‑FE) and the Scion xB (the export twin) repair manual, the 2005 Toyota bB uses a crush‑type sump plug washer on the engine oil drain plug. The listed Toyota genuine gasket is an aluminium drain plug washer, commonly supplied under part number 90430‑12031, and service literature specifies replacing the gasket at each oil change.

On this bB, the sump plug washer is a small but critical sealing component that sits between the drain plug head and the oil pan. Its job is to deform slightly as the plug is torqued, creating a reliable seal that prevents weeping or drips as the engine heats and cools. Without a fresh washer, the plug can bottom on the pan without sealing properly, or the old flattened washer can allow a slow leak that coats the underside with oil and dust.

For routine servicing, treat the washer as a consumable—fit a new one every time the engine oil is changed. Toyota workshop guidance for the 1NZ‑FE places the drain plug torque in the low-20 ft‑lb range (about 27 N·m). With a new washer installed and the seating face on the sump clean and burr‑free, that modest torque is all that’s needed to achieve a proper seal. Over‑tightening to “chase” a seal usually crushes the washer too far and risks damaging threads in the alloy pan.

Most owners and workshops in AU/NZ will be fine using a quality aluminium 12 mm ID crush washer sized for Toyota plugs. Copper alternatives can work, but stick with the correct thickness so the plug doesn’t run out of travel. If going genuine, ask for the Toyota drain plug gasket 90430‑12031 or an equivalent listing for the bB/xB with 1NZ‑FE.

• Replace the washer at each oil change (typically every 10,000 km or 12 months, depending on your schedule).
• Inspect the plug head and sump sealing face, clean off old gasket residue before refitting.
• Torque the plug to spec—don’t “nip it up” excessively.
• After the first drive, have a quick look under the car to confirm there’s no weep at the plug.

If there’s any sign of oil mist around the plug, or if the washer looks gouged, flattened wafer‑thin, or hard as nails, bin it and fit a new one. They’re cheap insurance against leaks and comebacks.

Popular questions

What size sump plug washer does a 2005 Toyota bB use?
The bB with the 1NZ‑FE/2NZ‑FE typically uses a 12 mm ID crush washer on the engine oil drain plug. Toyota’s common genuine part is 90430‑12031, and most aftermarket catalogues cross‑reference to that size and thickness. Always match the washer to the plug diameter and seating style on the car.

How often should the sump plug washer be replaced?
Replace it at every oil change. The washer is designed to crush once to seal, reusing an old, flattened gasket is a frequent cause of slow leaks. Fit a new washer, torque the plug to about 27 N·m, and you’re set.

Can a copper washer be used instead of the OEM aluminium washer?
Yes, provided it’s the correct size and thickness for the Toyota plug. Aluminium is the factory choice and seals with very low torque, but quality annealed copper washers are a workable alternative. Avoid fibre or random “close enough” sizes that don’t sit flat on the sump face.