thermostat problems on 2003 Chevrolet Venture

temp gauge goes up and down. cooling fans go on. how hard is it to remove thermastat on this van without taking half tha engine apart.

Asked by for the 2003 Chevrolet Venture
if the temp gauge goes up and down chances are you have got a head gasket leaking
if the h/gasket is leaking would there not be water on the ground because there is none. can this be verified be pressure testing?