Genuine Toyota Echo Thermostat

Toyota Echo Thermostat Parts Questions & Answers

• Thermostat
  90916-03093
  Q: How to test and replace a thermostat in a cooling system on Toyota Echo and Toyota Yaris?

  A: The thermostat in a cooling system can become slow to react or stick in the open or closed position as it ages. This can cause issues like slow warm-up or rapid overheating. Before assuming the thermostat is the problem, check the coolant level and ensure there are no airlocks. If the engine takes a long time to warm up or the temperature gauge is inaccurate, the thermostat may be stuck open or missing. If the engine runs hot and the Radiator top hose is not hot, the thermostat is likely stuck closed and needs replacing. To test the thermostat, start the engine and monitor the temperature of the radiator top hose. If it remains cold and then quickly warms up, the thermostat is working. If not, remove and test the thermostat by heating it in water. If it fails or sticks, replace it. Use a new O-ring and tighten the cover nut/bolt to the specified torque when refitting. Refill the cooling system.