OEM 2004 Toyota Avalon Thermostat

2004 Toyota Avalon Parts Questions & Experts Answers

• Q: How to service and repair the thermostat on 2004 Toyota Avalon?

  A: The service and repair tasks begin with coolant drain followed by 5 mm hexagon wrench use to remove three cap nuts and counter-clockwise disassembly of the fastener on the V-bank cover. Start the engine until it reaches normal operating temperature before you remove the air cleaner hose with resonator as well as disconnect heater hoses and No.2 ECT switch connector. The engine wire protector must be disconnected from the water inlet and right-hand cylinder head through removal of the clamp holding the nut. Remove the bolt connected to the water inlet pipe and left-hand cylinder head which also includes the O-ring. Tap the water inlet and thermostat loose by uninstalling three nuts and the gasket. Determine the serviceable condition of your thermostat through water immersion followed by temperature elevation until you reach verification that the valve opening occurs within 80 - 84 degrees Celsius (176 - 183 degrees Fahrenheit) range while needing a minimum valve lift of 10.0 mm (0.394 inch) at 95 degrees Celsius (203 degrees Fahrenheit). A complete closure of the valve should happen when the temperature stays below 40 degrees Celsius (104 degrees Fahrenheit); if the thermostat fails to meet requirements, replace the component immediately. The installation process requires placement of the thermostat inside the water pump with a new gasket while the jiggle valve should be lined up with the upper stud bolt. Begin the installation of the water inlet by applying torque to the 3 nuts until they reach 8 Nm (80 kgf-cm, 69 inch lbs.). After placing a new O-ring on the water inlet pipe and applying soapy water to it you can connect the pipe to the water inlet and bolt it to the left-hand cylinder head using a torque of 19.5 Nm (200 kgf-cm, 14 ft. lbs.). The procedure for handling the replacement and installation involves firstly reinstalling the engine wire protector followed by reattaching the No.2 ECT switch connector then reconnecting the heater hoses before reinstalling the air cleaner hose with resonator and using 3 cap nuts to secure the V-bank cover with a final step of pressing down the cover fastener. Begin by adding engine coolant to the system then start the engine and look for fluid leaks before examining the engine coolant amount.