Parts for your 2007 Toyota Ist-Sump plug washers

2007 Toyota ist sump plug washer — yes, it uses one

Based on Toyota’s technical literature, the 2007 Toyota ist (NCP110/NSP110 series) uses a sump plug washer on the engine oil drain plug. The Toyota Electronic Parts Catalogue for the JPN‑market ist lists a 12 mm drain plug gasket (commonly part number 90430‑12031), and the Toyota repair manual for the 1NZ‑FE/2NZ‑FE engines specifies “use a new gasket” when refitting the drain plug, torqued to 27 N·m. Those sources confirm the washer is fitted and considered a service item.

On this model, the sump plug washer is a simple, crush‑type gasket that sits between the drain plug head and the alloy steel sump face. When tightened to the correct spec, the soft aluminium ring deforms slightly to create a reliable, oil‑tight seal. That prevents annoying drips on the driveway and protects the sump threads from the kind of over‑tightening people tend to do when they’re trying to stop a seep without a fresh washer.

Because the washer is designed to deform once, Toyota’s guidance to replace it at each oil change is spot on. They’re inexpensive, easy to keep in the glovebox or toolbox, and they avoid the false economy of re‑using a flattened old ring that can cause a leak or tempt over‑torque. If a new washer isn’t available in a pinch, a careful assessment is key: if the old washer is visibly grooved, dished, or hardened, don’t risk it.

Handy servicing pointers for a 2007 Toyota ist sump plug washer:

• Washer type/size: 12 mm aluminium crush washer (Toyota 90430‑12031, or equivalent).
• Torque: 27 N·m (about 20 ft‑lb) on a clean, dry thread—no thread tape or sealant needed.
• Replace every oil change, inspect the plug for rounding or damaged threads while you’re there.
• Wipe both mating faces before install so the washer can seat and seal properly.

If there’s weeping after a service, first check the washer seating and torque before assuming the sump or plug is at fault. Persistent leaks with a new washer usually point to a nicked sump face, a scarred plug flange, or cross‑threading—each fixable with the right parts. For most owners in Australia and New Zealand, keeping a small pack of genuine or quality aftermarket 12 mm Toyota washers on hand makes every DIY oil change quicker, cleaner, and drama‑free.

Technical sources referenced: Toyota Electronic Parts Catalogue (JPN, model NCP110/NSP110, Oil Pan & Oil Strainer), and Toyota Repair Manual for 1NZ‑FE/2NZ‑FE engines, Lubrication section (drain plug installation notes).

Popular questions

What size sump plug washer does a 2007 Toyota ist use?
It uses a 12 mm aluminium crush washer, commonly referenced by Toyota as part number 90430‑12031. Many reputable aftermarket equivalents match this size and style.

How often should the sump plug washer be replaced on a 2007 Toyota ist?
Replace it at every oil change. The washer is designed to crush once, re‑using it risks drips or over‑tightening the plug to compensate.

What’s the correct torque for the drain plug on a 2007 Toyota ist?
Tighten the oil drain plug to 27 N·m on a clean, dry thread. That’s enough to crush the washer properly without stressing the sump threads.