OEM 2007 Toyota Sienna Thermostat

2007 Toyota Sienna Parts Questions & Experts Answers

• Q: How to service and repair the thermostat on 2007 Toyota Sienna?

  A: The service process for the thermostat begins with V-bank cover sub-assembly and No. 1 engine under cover removal. Purge the engine coolant before removing the front wheel right and the front fender apron seal right. The V-ribbed belt should be removed first along with disconnecting the No. 2 radiator hose connected to the engine. Disassemble the No. 2 idler pulley sub-assembly through the removal of bolt and idler pulley cover plate followed by idler pulley sub-assembly. To start replace the water inlet after unfastening its two nuts and removing the attaching hardware and thermostat while also removing the gasket. Examine the thermostat through a valve opening temperature test which should range from 80-84 degrees Celsius (176-183 degrees Fahrenheit). If the thermostat fails this examination it needs replacement. Check both the valve lift and opening temperature of the thermostat. The valve lift measurement at 95 degrees Celsius (203 degrees Fahrenheit) must exceed 7.7 mm (0.303 inch) while the valve should be completely shut below 40 degrees Celsius (104 degrees Fahrenheit). Replace the thermostat if necessary. The installation process requires mounting a new gasket to the thermostat before setting it up with its jiggle valve positioned at the top while keeping the assembly within a 10 degrees range. At first, tighten the two water inlet nuts using a torque of 10 Nm while maintaining 102 kgf-cm or 7 ft. lbs. Then secure the No. 2 idler pulley sub-assembly through the bolt application using 43 Nm as the torque value which equates to 438 kgf-cm or 32 ft. lbs. Reinstall the V-ribbed belt after connecting the No. 2 radiator hose to the engine and front fender apron seal RH together with front wheel RH. Ending the replacement process involves reinstalling the V-bank cover sub-assembly and checking for coolant leaks after adding fuel to the engine system and reinstalling the No. 1 engine under cover.