Where is the thermostat on a 1994 Plymouth yoyager?
Follow the top radiator hose until it meets the engine and it will be connected to a metal tube ( thermostat housing), that tube can be removed and underneath or ( inside ) you will find the thermostat, it is sandwiched between the housing ( tube) and the engine block. Be sure to scrape off all traces of the old gasket before putting in the new one and verify that the thermostat is in correctly spring side towards motor.
Changing a thermostat in a 1997 Plymouth Voyager is very easy to do. You will need to follow the radiator hose to the thermostat. You will then take the hose off the thermostat and remove the two bolts holding the thermostat in place. Make sure to clean the area before putting the new thermostat in place.