Check Car Thermostat How Could I Know Whether A Thermostat Got Stuck Closed Or Stuck Open

Someone said: To check, you should touch upper hose and lower hose. If one is hot and one is cold, it means thermostat stuck closed. But which is hot, which is cold: Upper? lower? Or it doesn’t matter? And, when is the thermostat stuck open? Thanks a lot
When thermostat stuck closed, usually upper hose is cold, lower hose is hot. But my overheated car is the other way around: Its upper hose is hot and lower hose is cold. Why? Could you advise? Thanks

Answers for The Question

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