Note:  Asked prior to using our product.

First, let's figure out why your thermostat is stuck.  I am assuming you know where your radiator hose is-- if your asking this question.  If not, use a search engine for images prior to my advice.

Start your engine and VERY CAREFULLY, during several minutes of warm up, lightly touch your radiator hose (connected to engine) where the thermostat is housed inside.   Is it hot?  If not, then you will need to purchase a new thermostat of the same temperature rating as your existing used/defective one. 

How the thermostat works?  It blocks the flow of coolant from the engine to the radiator until the engine reaches a temperature between 190 - 195 degrees F.   The thermostat may be stuck due to deteriorated mechanisms from normal wear & tear.  OR a steam pocket formed behind the thermostat not allowing coolant to pass behind.