Genuine Toyota 4Runner Thermostat

Toyota 4Runner Thermostat Parts Questions & Answers

• Thermostat
  90916-03100
  Q: How to replace the thermostat on 2003 through 2009 Toyota 4Runner?

  A: Before proceeding, check the coolant level and the drive belt tension, and then check the operation of the temperature gauge. If the engine takes a long time to warm up, the thermostat is probably stuck open. Replace the thermostat. If the engine runs hot, check the temperature of the left-side radiator hose (V6 models) or the right-side radiator hose (V8 models). If the hose isn't hot, the thermostat is probably stuck shut. Replace the thermostat. If the radiator hose is hot, then the coolant is circulating into the radiator and the thermostat is open. If the engine has overheated, it might have leaking cylinder head gaskets, scuffed pistons, or warped or cracked cylinder heads. To replace the thermostat, disconnect the cable from the negative terminal of the battery. Drain the cooling system. If you're working on a V6 model, remove the engine cover. Detach the thermostat housing from the engine. Be prepared for some coolant to spill as the gasket seal is broken. On V8 models, the radiator hose can be left attached to the housing, unless the housing itself is to be replaced. Remove the thermostat, noting the direction in which it was installed in the housing. Thoroughly clean the sealing surfaces. On V8 models, install a new gasket onto the thermostat. Make sure it fits evenly all the way around. On V6 models, install a new O-ring in the housing groove. On V8 models, install the thermostat and housing, positioning the jiggle pin, if equipped, at the highest point. Be sure the jiggle pin is not positioned more than 30 degrees right or left of the highest point. Tighten the housing fasteners to the torque and reinstall the remaining components in the reverse order of removal. Refill the cooling system, run the engine, and check for leaks and proper operation.
• Thermostat
  90916-03120
  Q: How to replace a thermostat in a cooling system on Toyota T100,1995 through 2004 Toyota Tacoma and 1996 through 2002 Toyota 4Runner?

  A: First thing, before you replace the thermostat, check the coolant level, drivebelt tension, and temperature gauge. For replacement of the thermostat, detach the negative cable on your battery, drain the cooling system, and gently detach the thermostat housing from the vehicle. Reinstall the thermostat as well as the housing, tighten the fasteners, and refill the cooling system.