Not to sound like a complete NooB, but which side of the engine is the thermostat housing setting on for the 1FZFE motor in a 97 Landcruiser? Is it on the lower right side of the motor or the upper left? Usually the thermostat sits right under the upper radiator house, but the TLC is a little different.
Here's a hint, when replacing the thermostat make sure the jiggle valve is in the top spot (if you dont have the FSM you might have missed that point) AND when yer filling up with coolant/water, fill it slowly, give the system some time to burp the air out, it helps to park the vehicle on an incline with the front higher than the rear. HTH.