Parts for your 2006 Toyota Ist-Sump plug washers

2006 Toyota ist sump plug washers — what they do and when to replace them

Based on Toyota’s own technical literature, the 2006 Toyota ist does use a sump plug washer. The Toyota Electronic Parts Catalogue for the NCP60/NCP61 ist (1NZ-FE/2NZ-FE engines) lists a separate oil drain plug gasket, typically aluminium crush type, part number 90430-12031, used with the M12 drain plug (e.g., 90341-12012). Toyota repair manual procedures for these engines specify refitting the plug with a new gasket and tightening to about 27 N·m. That combination confirms a washer is fitted and intended to be replaced at service time.

On the 2006 Toyota ist, the sump plug washer is a small but crucial seal that sits between the drain bolt and the sump (oil pan). When the bolt is torqued, the soft aluminium washer deforms slightly to take up any tiny imperfections in the mating faces, preventing slow weeps and proper leaks. Because it’s a crush design, it’s essentially a one‑use item—once compressed, it won’t spring back the same way next time.

During an oil change, the best practice is to swap the old washer for a new genuine‑spec piece (Toyota 90430‑12031 is the commonly listed gasket for these engines). Reusing a flattened washer can lead to a faint oil misting that only shows up as a damp film over time, or a drip that appears a day or two after the service. Either way, it’s cheap insurance to replace it every time the plug comes out.

Installation is straightforward: clean the sump face and the drain bolt flange, slide on the new washer, and tighten the bolt to the service spec—around 27 N·m for the 1NZ‑FE/2NZ‑FE as documented in Toyota repair procedures. Over‑tightening is a common trap, it can distort the washer too much or, worse, damage the sump threads. Under‑tightening can leave a weep. A torque wrench keeps it tidy.

Plenty of aftermarket washers exist (aluminium or copper). Aluminium matches the OEM crush behaviour and is generally preferred, if using copper, ensure it’s the correct size for the M12 plug and annealed if reusable styles are chosen. If the plug has been chewed up in the past, replace it along with the washer so the sealing face is smooth. After the first post‑service drive, a quick glance under the car to check for any fresh oil at the plug is a simple way to confirm all’s well.

• Washer type: aluminium crush
• Typical size: for M12 drain plug (Toyota PN 90430‑12031)
• Tightening torque: about 27 N·m (as per Toyota procedures)
• Replace: at every oil change or any time the plug is removed

Popular questions

What size sump plug washer does a 2006 Toyota ist use?

It uses an aluminium crush washer for an M12 drain plug. The commonly referenced Toyota part number is 90430‑12031, which suits the 1NZ‑FE/2NZ‑FE engines used in the 2006 ist.

How often should the sump plug washer be replaced on a 2006 Toyota ist?

Swap it at every oil change, or any time the drain plug is removed. The washer is designed to crush once, so reusing it increases the risk of weeping or drips.

What torque should the oil drain plug be tightened to?

About 27 N·m for the 1NZ‑FE/2NZ‑FE engines found in the 2006 ist, as specified in Toyota repair procedures. Using a torque wrench helps avoid over‑tightening and protects the sump threads.