When you take out a thermostat in a 98 Plymouth Breeze do you put something in its place?

Yes, when you remove the thermostat from a 1998 Plymouth Breeze, you typically need to replace it with a new thermostat before reassembling the cooling system. If you're temporarily removing the thermostat for testing purposes, you can use a bypass or a fitting to seal the housing, but it's essential to install a new thermostat as soon as possible to ensure proper engine temperature regulation. Running the engine without a thermostat can lead to overheating or inefficient cooling.