You can check the t-stat by lowering the coolant level and popping the upper rad hose off the housing and look down.....Unfortunately, that won't help you ID a bad T-sat, but will eliminate an installation error. Yes, make sure it is cool, and that there is no pressure in the system when you do this.
Ok. Thank you. Are thermostats fairly generic? Like if I take it to an auto parts store would they have one, or is it a specialty classic car type thing?