Better than frozen shut.
It closes to provide early heat to the intake manifold. Once warmed up, it opens. But it sounds like you are missing the coiled spring that connects to the end of the shaft ex̌ternally which controls opening and closing.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12
'52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
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