Parts for your 2004 Lexus Is-Thermostat housing

2004 Lexus IS thermostat housing — what it does and when to replace it

Technical sources confirm the 2004 Lexus IS uses a thermostat housing. The Lexus/Toyota factory repair manual for the first‑gen IS (XE10, IS200/IS300, Cooling section) outlines a thermostat set into the water inlet (thermostat housing) on the engine. The Toyota Electronic Parts Catalogue (EPC), Cooling group, also lists the “water inlet/thermostat housing” and associated gasket/O‑ring for these engines (1G‑FE for IS200