Toyota 90916-03100 Thermostat

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.

16346-50010

Both thermostats are interchangeable but do not include a gasket. Those have to be purchased separately.

The dimensions are as following: 2.8inx2.6inx2.4in

No, there is no o-ring needed