OEM 2003 Toyota Tundra Thermostat

2003 Toyota Tundra Parts Questions & Experts Answers

• Q: How to service the thermostat on 2003 Toyota Tundra?

  A: Draining the engine coolant constitutes the initial step when servicing the thermostat. Begin by unfastening the 3 nuts followed by the wire clamp and water inlet together with the thermostat from the water pump and then separate the gasket from the thermostat. Place the thermostat in water while heating it until you verify that the valve opens between 80 and 84 degrees Celsius (176 - 183 degrees Fahrenheit), if this check reveals non-compliance with these specifications then you must replace the thermostat. A thermostat requires replacement if its valve lift does not reach 8.5 mm (0.335 inch) while the water reaches 95 degrees Celsius (203 degrees Fahrenheit). A fully closed valve position becomes necessary when the temperature stays below 40 degrees Celsius (104 degrees Fahrenheit); any failure to close the valve requires replacement of the thermostat. Following these steps for installation requires the use of a new gasket and placement of the thermostat with the jiggle valve facing down then securing the water inlet bolts with 20 Nm (200 kgf-cm, 14 ft. lbs.) torque. You must start by attaching the lower radiator hose and adding engine coolant before starting the engine to check for coolant leaks before verifying the new engine coolant level.