OEM 2001 Toyota Avalon Thermostat

2001 Toyota Avalon Parts Questions & Experts Answers

• Q: How to service and repair the thermostat on 2001 Toyota Avalon?

  A: The service and repair process begins with draining engine coolant followed by removing the V-bank cover through a 5 mm hexagon wrench that loosens the cap nuts and counterclockwise motion of the cover fastener. After engine warming reaches its operating temperature the technician will disconnect the air cleaner hose with resonator along with heater hoses before removing the No.2 ECT switch connector. For this step disconnect the engine wire protector by separating the clamp from the water inlet and right-hand cylinder head through nut removal. Start removal of the water inlet pipe from the water inlet and left-hand cylinder head that requires both bolt and O-ring removal from the inlet pipe. You must remove the water inlet while also taking out the thermostat by extracting the 3 nuts along with the thermostat gasket. Check the thermostat through water immersion while applying gradual heat to verify its valve opening temperature falls within 80 - 84 degrees Celsius (176 - 183 degrees Fahrenheit) and the valve lift reaches 10.0 mm (0.394 inch) at 95 degrees Celsius (203 degrees Fahrenheit). Perform replacement of the thermostat when any test results show deviations from specifications related to valve function at low temp or when the value fails to close below 40 degrees Celsius (104 degrees Fahrenheit). Install the thermostat inside the water pump while using a new gasket and ensure the jiggle valve faces the upper stud bolt. First install the 3 nuts on the water inlet and torque them to 8 Nm (80 kgf-cm, 69 inch lbs.). Next install a new O-ring on the water inlet pipe and apply soapy water before connecting it to the left-hand cylinder head and securing it with a bolt that receives a torque of 19.5 Nm (200 kgf-cm, 14 ft. lbs.). Reinstall the engine wire protector followed by hooking up the No.2 ECT switch connector and hosing the heater before reinstalling the air cleaner hose with resonator and installing the V-bank cover through the application of 5 mm hexagon wrench and 3 cap nuts with the additional step of pressing down the cover fastener. The process begins with engine coolant addition while the engine is started to examine for any fluid leakage before checking the engine coolant level once more.