1995 Honda Prelude thermostat replacementThe thermostat is located on the left side rear of the engine at the end of the lower radiator hose. There are three bolts in a triangular bolt pattern fastening the thermostat housing cap to the housing body. The cap also has the coolant sensor in it. The orientation of the thermostat is critical. There are a pair of holes that locate the gasket pins in the main engine body. The by-pass rivet(the floating pin on the flange of the thermostat)is located between those holes.
Note that removal of the air intake tube is necessary to access the thermostat housing.