Where is the thermostat located on a 1991 Chevy Caprice Classic 5.0L?

It is at the engine end of the upper rad hose. When replacing it make sure the spring goes toward the engine,.

Answer

If you live in a warm climate use a 180 degree thermostat. For cold climates use a 195. One caution on this job, use blue RTV to seal the gasket and do not overtightene as you can break the "ears" of the cover.

VBdenny

No matter where you live you HAVE to use a 195 degree thermostat as the engine computer must recognize that temperature so as to get the proper fuel/ air ratio.