Century Estate Wagon V6-231 3.8L VIN 3 FI (1987)
Thermostatic Air Cleaner Vacuum Switch: Description and Operation
Thermostatic Air Cleaner Thermal Check Valve (TAC-TCV)
This valve is a one-way check valve and closes at 80° F. When the valve's temperature reaches 95° F, it opens and allows vacuum to flow in both
directions.