They are actually designed with wax and rubber inside so they can get stuck either way. Most people never notice their stats are stuck open until they want some heat in the vehicle and there is none.

Ever notice that thermostats are the only thing on a vehicle that still uses 1930's non-updated technology?

 

sure have...and its quite a silly notion.

 

It's going to be 80F here in FL today...I wouldn't run a your truck without a functioning radiator, too much risk of seriously damaging the engine, IMO.