Replace the thermostaton a 1987 Toyota LE Van?

Answer 1

Probably located at the engine end of the upper radiator hose in a removable housing Drain about 1 gallon of coolant from the radiator Remove housing at end of radiator hose Make note how thermostat is installed Clean both surfaces Replace thermostat and gasket Re-fill coolant slowly to prevent an "airlock" Start engine and look for leaks Run engine to normal operating temperature with heater on Re-check coolant level