The Honda Civic has been around since 1973 and for Honda, it has remained one of their most popular models. It's possible to see a Honda civic of just about any age running down the streets because of this. The Civic's basic engine has not changed much over the years, so engine repair work is pretty consistent from year to year. This means completing repairs like replacing a broken thermostat will be very similar on all versions of the Civic.
Locate the thermostat housing by tracing the top radiator hose to the location where the hose connects to the intake manifold. Remove the hose from the thermostat housing with a screwdriver. Push the hose off to the side so you can remove the thermostat housing.
Remove the 10mm bolts that hold the thermostat housing onto the intake manifold of the Civic, and pull the housing off of the intake manifold.
Pull the thermostat and the thermostat gasket out of the intake manifold, and discard them both. They will not be used again.
Place the new thermostat into the intake manifold. It will sit on a machined ledge just under the antifreeze. The end that is marked "top" will not be submerged into the antifreeze.
Apply an RTV silicone gasket maker onto the bottom of the thermostat housing, and then bolt the thermostat housing back onto the intake manifold of the Civic.
Place the radiator hose back onto the thermostat housing, and secure the clamp that holds it into place.