Parts for your 2001 Toyota Echo|yaris-Thermostat

2001 Toyota Echo/Yaris Thermostat — What it does and when to replace it

Yes, a thermostat is fitted and relevant on the 2001 Toyota Echo/Yaris. Technical sources including the Toyota Echo/Yaris Repair Manual (1999–2005), the Toyota Electronic Parts Catalogue, and mainstream workshop manuals all specify a wax‑pellet thermostat in the water inlet housing on the 1SZ‑FE (1.0 L), 2NZ‑FE (1.3 L) and 1NZ‑FE (1.5 L) engines. Service data notes an opening temperature around 80–84°C and fully open near 95°C, confirming its role in engine warm‑up and cooling control.

On this Echo/Yaris, the thermostat’s job is to help the engine reach operating temp quickly, then keep it there. It stays closed when cold so the engine warms up faster (better fuel economy and smoother running), then opens to let coolant circulate through the radiator once it’s up to temperature. If it sticks shut, you’ll see overheating