Parts for your 2006 Lexus Is-Sump plug washers

2006 Lexus IS sump plug washers — what they do and when to replace them

Yes — a sump plug washer is used on the 2006 Lexus IS. Lexus/Toyota service literature for the second‑generation IS (GSE2#/USE2#, including IS250/IS350, and IS220d in some markets) specifies fitting a new oil drain plug gasket at each engine oil change. The Toyota/Lexus Electronic Parts Catalog lists a 12 mm crush washer for these engines (commonly p/n 90430‑12031 or its supersessions), and the Lexus IS 2006 Repair Manual (via Toyota TIS) instructs to “install the drain plug with a new gasket.”

On this model, the sump plug washer — also called a crush washer — sits between the drain plug and the sump. When tightened, the soft metal washer deforms to create a reliable seal that handles heat cycles, vibration, and pressure changes. That stops the little weeps that turn into drips on the driveway and the whiff of burning oil on hot exhaust components.

Because it’s designed to deform once, the washer is considered a single‑use item. Reusing it can lead to seepage, oil misting on the undertray, or a slow drip that shows up as a low oil level over time. Best practice on a 2006 Lexus IS is to replace the sump plug washer at every oil change or any time the drain plug is removed. It’s an inexpensive part that protects a far more expensive alloy sump and keeps the plug torque predictable.

Owners and technicians in Australia and New Zealand will typically choose an OEM aluminium washer, though quality copper alternatives also work. Make sure the inner diameter and profile match the vehicle’s M12 drain plug used on most IS variants, confirm by VIN if unsure, especially for diesel models. Clean the plug and sump seating face, check for nicks, and tighten the plug to the workshop manual specification — over‑tightening can damage threads in the alloy sump. Avoid stacking old washers or fitting generic rubber/fibre seals not rated for hot engine oil.

• Replace the sump plug washer at every oil change, or whenever the plug is removed.
• Watch for weeping around the plug, fresh drips on the undertray, or a hot oil smell as signs it’s due.
• Use a correct‑size Toyota/Lexus‑spec crush washer, don’t double up or reuse flattened washers.
• Clean the sealing surfaces and tighten to the service manual torque to protect the alloy sump.

What size sump plug washer does a 2006 Lexus IS use?

Most 2006 IS models use a 12 mm ID Toyota/Lexus crush washer (commonly 90430‑12031 or equivalent). Variations can exist by engine, so it’s smart to confirm against the VIN or engine code (e.g., 4GR‑FSE, 2GR‑FSE, 2AD‑FHV) before buying.

How often should the sump plug washer be replaced on a 2006 Lexus IS?

Every oil change, without fail — and any time the drain plug is removed. It’s a single‑use crush washer designed to deform once for a proper seal.

Can a rubber or fibre washer be used instead of the OEM crush washer?

It’s best to stick with an OEM‑style aluminium (or quality copper) crush washer. Generic rubber or fibre washers can extrude or harden with heat and may leak on the IS’s alloy sump interface.